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What are the genetic changes related to CHARGE syndrome ?
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Mutations in the CHD7 gene cause more than half of all cases of CHARGE syndrome. The CHD7 gene provides instructions for making a protein that most likely regulates gene activity (expression) by a process known as chromatin remodeling. Chromatin is the complex of DNA and protein that packages DNA into chromosomes. The structure of chromatin can be changed (remodeled) to alter how tightly DNA is packaged. Chromatin remodeling is one way gene expression is regulated during development. When DNA is tightly packed, gene expression is lower than when DNA is loosely packed. Most mutations in the CHD7 gene lead to the production of an abnormally short, nonfunctional CHD7 protein, which presumably disrupts chromatin remodeling and the regulation of gene expression. Changes in gene expression during embryonic development likely cause the signs and symptoms of CHARGE syndrome. About one-third of individuals with CHARGE syndrome do not have an identified mutation in the CHD7 gene. Researchers suspect that other genetic and environmental factors may be involved in these individuals.
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Is CHARGE syndrome inherited ?
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CHARGE syndrome is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most cases result from new mutations in the CHD7 gene and occur in people with no history of the disorder in their family. In rare cases, an affected person inherits the mutation from an affected parent.
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What are the treatments for CHARGE syndrome ?
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These resources address the diagnosis or management of CHARGE syndrome: - Gene Review: Gene Review: CHARGE Syndrome - Genetic Testing Registry: CHARGE association - MedlinePlus Encyclopedia: Choanal atresia - MedlinePlus Encyclopedia: Coloboma - MedlinePlus Encyclopedia: Facial Paralysis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) Charcot-Marie-Tooth disease ?
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Charcot-Marie-Tooth disease is a group of progressive disorders that affect the peripheral nerves. Peripheral nerves connect the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, heat, and sound. Damage to the peripheral nerves can result in loss of sensation and wasting (atrophy) of muscles in the feet, legs, and hands. Charcot-Marie-Tooth disease usually becomes apparent in adolescence or early adulthood, but onset may occur anytime from early childhood through late adulthood. Symptoms of Charcot-Marie-Tooth disease vary in severity, even among members of the same family. Some people never realize they have the disorder, but most have a moderate amount of physical disability. A small percentage of people experience severe weakness or other problems which, in rare cases, can be life-threatening. In most affected individuals, however, Charcot-Marie-Tooth disease does not affect life expectancy. Typically, the earliest symptoms of Charcot-Marie-Tooth disease involve balance difficulties, clumsiness, and muscle weakness in the feet. Affected individuals may have foot abnormalities such as high arches (pes cavus), flat feet (pes planus), or curled toes (hammer toes). They often have difficulty flexing the foot or walking on the heel of the foot. These difficulties may cause a higher than normal step (or gait) and increase the risk of ankle injuries and tripping. As the disease progresses, muscles in the lower legs usually weaken, but leg and foot problems rarely require the use of a wheelchair. Affected individuals may also develop weakness in the hands, causing difficulty with daily activities such as writing, fastening buttons, and turning doorknobs. People with this disorder typically experience a decreased sensitivity to touch, heat, and cold in the feet and lower legs, but occasionally feel aching or burning sensations. In some cases, affected individuals experience gradual hearing loss, deafness, or loss of vision. There are several types of Charcot-Marie-Tooth disease. Type 1 Charcot-Marie-Tooth disease (CMT1) is characterized by abnormalities in myelin, the fatty substance that covers nerve cells, protecting them and helping to conduct nerve impulses. These abnormalities slow the transmission of nerve impulses. Type 2 Charcot-Marie-Tooth disease (CMT2) is characterized by abnormalities in the fiber, or axon, that extends from a nerve cell body and transmits nerve impulses. These abnormalities reduce the strength of the nerve impulse. Type 4 Charcot-Marie-Tooth disease (CMT4) affects either the axon or myelin and is distinguished from the other types by its pattern of inheritance. In intermediate forms of Charcot-Marie-Tooth disease, the nerve impulses are both slowed and reduced in strength, probably due to abnormalities in both axons and myelin. Type X Charcot-Marie-Tooth disease (CMTX) is caused by mutations in a gene on the X chromosome, one of the two sex chromosomes. Within the various types of Charcot-Marie-Tooth disease, subtypes (such as CMT1A, CMT1B, CMT2A, CMT4A, and CMTX1) are distinguished by the specific gene that is altered. Sometimes other, more historical names are used to describe this disorder. For example, Roussy-Levy syndrome is a form of Charcot-Marie-Tooth disease defined by the additional feature of rhythmic shaking (tremors). Dejerine-Sottas syndrome is a term sometimes used to describe a severe, early childhood form of Charcot-Marie-Tooth disease; it is also sometimes called Charcot-Marie-Tooth disease type 3 (CMT3). Depending on the specific gene that is altered, this severe, early onset form of the disorder may also be classified as CMT1 or CMT4. CMTX5 is also known as Rosenberg-Chutorian syndrome. Some researchers believe that this condition is not actually a form of Charcot-Marie-Tooth disease. Instead, they classify it as a separate disorder characterized by peripheral nerve problems, deafness, and vision loss.
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How many people are affected by Charcot-Marie-Tooth disease ?
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Charcot-Marie-Tooth disease is the most common inherited disorder that involves the peripheral nerves, affecting an estimated 150,000 people in the United States. It occurs in populations worldwide with a prevalence of about 1 in 2,500 individuals.
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What are the genetic changes related to Charcot-Marie-Tooth disease ?
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Charcot-Marie-Tooth disease is caused by mutations in many different genes. These genes provide instructions for making proteins that are involved in the function of peripheral nerves in the feet, legs, and hands. The gene mutations that cause Charcot-Marie-Tooth disease affect the function of the proteins in ways that are not fully understood; however, they likely impair axons, which transmit nerve impulses, or affect the specialized cells that produce myelin. As a result, peripheral nerve cells slowly lose the ability to stimulate the muscles and to transmit sensory signals to the brain. The list of genes associated with Charcot-Marie-Tooth disease continues to grow as researchers study this disorder. Different mutations within a particular gene may cause signs and symptoms of differing severities or lead to different types of Charcot-Marie-Tooth disease. CMT1 is caused by mutations in the following genes: PMP22 (CMT1A and CMT1E), MPZ (CMT1B), LITAF (CMT1C), EGR2 (CMT1D), and NEFL (CMT1F). CMT2 can result from alterations in many genes, including MFN2 and KIF1B (CMT2A); RAB7A (CMT2B); LMNA (CMT2B1); TRPV4 (CMT2C); BSCL2 and GARS (CMT2D); NEFL (CMT2E); HSPB1 (CMT2F); MPZ (CMT2I and CMT2J); GDAP1 (CMT2K); and HSPB8 (CMT2L). Certain DNM2 gene mutations also cause a form of CMT2. CMT4 is caused by mutations in the following genes: GDAP1 (CMT4A), MTMR2 (CMT4B1), SBF2 (CMT4B2), SH3TC2 (CMT4C), NDRG1 (CMT4D), EGR2 (CMT4E), PRX (CMT4F), FGD4 (CMT4H), and FIG4 (CMT4J). Intermediate forms of the disorder can be caused by alterations in genes including DNM2, MPZ, YARS, and GDAP1. CMTX is caused by mutations in genes including GJB1 (CMTX1) and PRPS1 (CMTX5). Mutations in additional genes, some of which have not been identified, also cause various forms of Charcot-Marie-Tooth disease.
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Is Charcot-Marie-Tooth disease inherited ?
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The pattern of inheritance varies with the type of Charcot-Marie-Tooth disease. CMT1, most cases of CMT2, and most intermediate forms are inherited in an autosomal dominant pattern. This pattern of inheritance means that one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one affected parent. CMT4, a few CMT2 subtypes, and some intermediate forms are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition. CMTX is inherited in an X-linked dominant pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome. The inheritance is dominant if one copy of the altered gene is sufficient to cause the condition. In most cases, affected males, who have the alteration on their only copy of the X chromosome, experience more severe symptoms of the disorder than females, who have two X chromosomes. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. All daughters of affected men will have one altered X chromosome, but they may only have mild symptoms of the disorder. Some cases of Charcot-Marie-Tooth disease result from a new mutation and occur in people with no history of the disorder in their family.
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What are the treatments for Charcot-Marie-Tooth disease ?
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These resources address the diagnosis or management of Charcot-Marie-Tooth disease: - Gene Review: Gene Review: Charcot-Marie-Tooth Hereditary Neuropathy Overview - Gene Review: Gene Review: Charcot-Marie-Tooth Neuropathy Type 1 - Gene Review: Gene Review: Charcot-Marie-Tooth Neuropathy Type 2 - Gene Review: Gene Review: Charcot-Marie-Tooth Neuropathy Type 2A - Gene Review: Gene Review: Charcot-Marie-Tooth Neuropathy Type 2E/1F - Gene Review: Gene Review: Charcot-Marie-Tooth Neuropathy Type 4 - Gene Review: Gene Review: Charcot-Marie-Tooth Neuropathy Type 4A - Gene Review: Gene Review: Charcot-Marie-Tooth Neuropathy Type 4C - Gene Review: Gene Review: Charcot-Marie-Tooth Neuropathy X Type 1 - Gene Review: Gene Review: Charcot-Marie-Tooth Neuropathy X Type 5 - Gene Review: Gene Review: DNM2-Related Intermediate Charcot-Marie-Tooth Neuropathy - Gene Review: Gene Review: GARS-Associated Axonal Neuropathy - Gene Review: Gene Review: TRPV4-Associated Disorders - Genetic Testing Registry: Charcot-Marie-Tooth disease - Genetic Testing Registry: Charcot-Marie-Tooth disease dominant intermediate 3 - Genetic Testing Registry: Charcot-Marie-Tooth disease type 1B - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2B - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2B1 - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2B2 - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2C - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2D - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2E - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2F - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2I - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2J - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2K - Genetic Testing Registry: Charcot-Marie-Tooth disease type 2P - Genetic Testing Registry: Charcot-Marie-Tooth disease, X-linked recessive, type 5 - Genetic Testing Registry: Charcot-Marie-Tooth disease, axonal, type 2O - Genetic Testing Registry: Charcot-Marie-Tooth disease, axonal, with vocal cord paresis, autosomal recessive - Genetic Testing Registry: Charcot-Marie-Tooth disease, dominant intermediate C - Genetic Testing Registry: Charcot-Marie-Tooth disease, dominant intermediate E - Genetic Testing Registry: Charcot-Marie-Tooth disease, recessive intermediate A - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 1C - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 2A1 - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 2A2 - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 2L - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 2N - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 4A - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 4B1 - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 4B2 - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 4C - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 4D - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 4H - Genetic Testing Registry: Charcot-Marie-Tooth disease, type 4J - Genetic Testing Registry: Charcot-Marie-Tooth disease, type I - Genetic Testing Registry: Charcot-Marie-Tooth disease, type IA - Genetic Testing Registry: Charcot-Marie-Tooth disease, type ID - Genetic Testing Registry: Charcot-Marie-Tooth disease, type IE - Genetic Testing Registry: Charcot-Marie-Tooth disease, type IF - Genetic Testing Registry: Congenital hypomyelinating neuropathy - Genetic Testing Registry: DNM2-related intermediate Charcot-Marie-Tooth neuropathy - Genetic Testing Registry: Dejerine-Sottas disease - Genetic Testing Registry: Roussy-Lvy syndrome - Genetic Testing Registry: X-linked hereditary motor and sensory neuropathy - MedlinePlus Encyclopedia: Charcot-Marie-Tooth Disease - MedlinePlus Encyclopedia: Hammer Toe - MedlinePlus Encyclopedia: High Arch These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) hystrix-like ichthyosis with deafness ?
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Hystrix-like ichthyosis with deafness (HID) is a disorder characterized by dry, scaly skin (ichthyosis) and hearing loss that is usually profound. Hystrix-like means resembling a porcupine; in this type of ichthyosis, the scales may be thick and spiky, giving the appearance of porcupine quills. Newborns with HID typically develop reddened skin. The skin abnormalities worsen over time, and the ichthyosis eventually covers most of the body, although the palms of the hands and soles of the feet are usually only mildly affected. Breaks in the skin may occur and in severe cases can lead to life-threatening infections. Affected individuals have an increased risk of developing a type of skin cancer called squamous cell carcinoma, which can also affect mucous membranes such as the inner lining of the mouth. People with HID may also have patchy hair loss caused by scarring on particular areas of skin.
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How many people are affected by hystrix-like ichthyosis with deafness ?
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HID is a rare disorder. Its prevalence is unknown.
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What are the genetic changes related to hystrix-like ichthyosis with deafness ?
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HID is caused by mutations in the GJB2 gene. This gene provides instructions for making a protein called gap junction beta 2, more commonly known as connexin 26. Connexin 26 is a member of the connexin protein family. Connexin proteins form channels called gap junctions that permit the transport of nutrients, charged atoms (ions), and signaling molecules between neighboring cells that are in contact with each other. Gap junctions made with connexin 26 transport potassium ions and certain small molecules. Connexin 26 is found in cells throughout the body, including the inner ear and the skin. In the inner ear, channels made from connexin 26 are found in a snail-shaped structure called the cochlea. These channels may help to maintain the proper level of potassium ions required for the conversion of sound waves to electrical nerve impulses. This conversion is essential for normal hearing. In addition, connexin 26 may be involved in the maturation of certain cells in the cochlea. Connexin 26 also plays a role in the growth and maturation of the outermost layer of skin (the epidermis). At least one GJB2 gene mutation has been identified in people with HID. This mutation changes a single protein building block (amino acid) in connexin 26. The mutation is thought to result in channels that constantly leak ions, which impairs the health of the cells and increases cell death. Death of cells in the skin and the inner ear may underlie the signs and symptoms of HID. Because the GJB2 gene mutation identified in people with HID also occurs in keratitis-ichthyosis-deafness syndrome (KID syndrome), a disorder with similar features and the addition of eye abnormalities, many researchers categorize KID syndrome and HID as a single disorder, which they call KID/HID. It is not known why some people with this mutation have eye problems while others do not.
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Is hystrix-like ichthyosis with deafness inherited ?
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This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family.
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What are the treatments for hystrix-like ichthyosis with deafness ?
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These resources address the diagnosis or management of hystrix-like ichthyosis with deafness: - Foundation for Ichthyosis and Related Skin Types: Ichthyosis Hystrix - Genetic Testing Registry: Hystrix-like ichthyosis with deafness These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) inherited thyroxine-binding globulin deficiency ?
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Inherited thyroxine-binding globulin deficiency is a genetic condition that typically does not cause any health problems. Thyroxine-binding globulin is a protein that carries hormones made or used by the thyroid gland, which is a butterfly-shaped tissue in the lower neck. Thyroid hormones play an important role in regulating growth, brain development, and the rate of chemical reactions in the body (metabolism). Most of the time, these hormones circulate in the bloodstream attached to thyroxine-binding globulin and similar proteins. If there is a shortage (deficiency) of thyroxine-binding globulin, the amount of circulating thyroid hormones is reduced. Researchers have identified two forms of inherited thyroxine-binding globulin deficiency: the complete form (TBG-CD), which results in a total loss of thyroxine-binding globulin, and the partial form (TBG-PD), which reduces the amount of this protein or alters its structure. Neither of these conditions causes any problems with thyroid function. They are usually identified during routine blood tests that measure thyroid hormones. Although inherited thyroxine-binding globulin deficiency does not cause any health problems, it can be mistaken for more serious thyroid disorders (such as hypothyroidism). Therefore, it is important to diagnose inherited thyroxine-binding globulin deficiency to avoid unnecessary treatments.
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How many people are affected by inherited thyroxine-binding globulin deficiency ?
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The complete form of inherited thyroxine-binding globulin deficiency, TBG-CD, affects about 1 in 15,000 newborns worldwide. The partial form, TBG-PD, affects about 1 in 4,000 newborns. These conditions appear to be more common in the Australian Aborigine population and in the Bedouin population of southern Israel.
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What are the genetic changes related to inherited thyroxine-binding globulin deficiency ?
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Inherited thyroxine-binding globulin deficiency results from mutations in the SERPINA7 gene. This gene provides instructions for making thyroxine-binding globulin. Some mutations in the SERPINA7 gene prevent the production of a functional protein, causing TBG-CD. Other mutations reduce the amount of this protein or alter its structure, resulting in TBG-PD. Researchers have also described non-inherited forms of thyroxine-binding globulin deficiency, which are more common than the inherited form. Non-inherited thyroxine-binding globulin deficiency can occur with a variety of illnesses and is a side effect of some medications.
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Is inherited thyroxine-binding globulin deficiency inherited ?
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Inherited thyroxine-binding globulin deficiency has an X-linked pattern of inheritance. The SERPINA7 gene is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), a mutation in the only copy of the gene in each cell causes partial or complete inherited thyroxine-binding globulin deficiency. In females (who have two X chromosomes), a mutation in one of the two copies of the gene in each cell reduces the amount of thyroxine-binding globulin. However, their levels of this protein are usually within the normal range. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
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What are the treatments for inherited thyroxine-binding globulin deficiency ?
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These resources address the diagnosis or management of inherited thyroxine-binding globulin deficiency: - American Thyroid Association: Thyroid Function Tests - MedlinePlus Encyclopedia: Serum TBG Level These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) harlequin ichthyosis ?
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Harlequin ichthyosis is a severe genetic disorder that mainly affects the skin. Infants with this condition are born with very hard, thick skin covering most of their bodies. The skin forms large, diamond-shaped plates that are separated by deep cracks (fissures). These skin abnormalities affect the shape of the eyelids, nose, mouth, and ears, and limit movement of the arms and legs. Restricted movement of the chest can lead to breathing difficulties and respiratory failure. The skin normally forms a protective barrier between the body and its surrounding environment. The skin abnormalities associated with harlequin ichthyosis disrupt this barrier, making it more difficult for affected infants to control water loss, regulate their body temperature, and fight infections. Infants with harlequin ichthyosis often experience an excessive loss of fluids (dehydration) and develop life-threatening infections in the first few weeks of life. It used to be very rare for affected infants to survive the newborn period. However, with intensive medical support and improved treatment, people with this disorder now have a better chance of living into childhood and adolescence.
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How many people are affected by harlequin ichthyosis ?
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Harlequin ichthyosis is very rare; its exact incidence is unknown.
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What are the genetic changes related to harlequin ichthyosis ?
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Mutations in the ABCA12 gene cause harlequin ichthyosis. The ABCA12 gene provides instructions for making a protein that is essential for the normal development of skin cells. This protein plays a major role in the transport of fats (lipids) in the outermost layer of skin (the epidermis). Some mutations in the ABCA12 gene prevent the cell from making any ABCA12 protein. Other mutations lead to the production of an abnormally small version of the protein that cannot transport lipids properly. A loss of functional ABCA12 protein disrupts the normal development of the epidermis, resulting in the hard, thick scales characteristic of harlequin ichthyosis.
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Is harlequin ichthyosis inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for harlequin ichthyosis ?
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These resources address the diagnosis or management of harlequin ichthyosis: - Gene Review: Gene Review: Autosomal Recessive Congenital Ichthyosis - Genetic Testing Registry: Autosomal recessive congenital ichthyosis 4B These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) neurofibromatosis type 1 ?
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Neurofibromatosis type 1 is a condition characterized by changes in skin coloring (pigmentation) and the growth of tumors along nerves in the skin, brain, and other parts of the body. The signs and symptoms of this condition vary widely among affected people. Beginning in early childhood, almost all people with neurofibromatosis type 1 have multiple caf-au-lait spots, which are flat patches on the skin that are darker than the surrounding area. These spots increase in size and number as the individual grows older. Freckles in the underarms and groin typically develop later in childhood. Most adults with neurofibromatosis type 1 develop neurofibromas, which are noncancerous (benign) tumors that are usually located on or just under the skin. These tumors may also occur in nerves near the spinal cord or along nerves elsewhere in the body. Some people with neurofibromatosis type 1 develop cancerous tumors that grow along nerves. These tumors, which usually develop in adolescence or adulthood, are called malignant peripheral nerve sheath tumors. People with neurofibromatosis type 1 also have an increased risk of developing other cancers, including brain tumors and cancer of blood-forming tissue (leukemia). During childhood, benign growths called Lisch nodules often appear in the colored part of the eye (the iris). Lisch nodules do not interfere with vision. Some affected individuals also develop tumors that grow along the nerve leading from the eye to the brain (the optic nerve). These tumors, which are called optic gliomas, may lead to reduced vision or total vision loss. In some cases, optic gliomas have no effect on vision. Additional signs and symptoms of neurofibromatosis type 1 include high blood pressure (hypertension), short stature, an unusually large head (macrocephaly), and skeletal abnormalities such as an abnormal curvature of the spine (scoliosis). Although most people with neurofibromatosis type 1 have normal intelligence, learning disabilities and attention deficit hyperactivity disorder (ADHD) occur frequently in affected individuals.
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How many people are affected by neurofibromatosis type 1 ?
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Neurofibromatosis type 1 occurs in 1 in 3,000 to 4,000 people worldwide.
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What are the genetic changes related to neurofibromatosis type 1 ?
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Mutations in the NF1 gene cause neurofibromatosis type 1. The NF1 gene provides instructions for making a protein called neurofibromin. This protein is produced in many cells, including nerve cells and specialized cells surrounding nerves (oligodendrocytes and Schwann cells). Neurofibromin acts as a tumor suppressor, which means that it keeps cells from growing and dividing too rapidly or in an uncontrolled way. Mutations in the NF1 gene lead to the production of a nonfunctional version of neurofibromin that cannot regulate cell growth and division. As a result, tumors such as neurofibromas can form along nerves throughout the body. It is unclear how mutations in the NF1 gene lead to the other features of neurofibromatosis type 1, such as caf-au-lait spots and learning disabilities.
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Is neurofibromatosis type 1 inherited ?
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Neurofibromatosis type 1 is considered to have an autosomal dominant pattern of inheritance. People with this condition are born with one mutated copy of the NF1 gene in each cell. In about half of cases, the altered gene is inherited from an affected parent. The remaining cases result from new mutations in the NF1 gene and occur in people with no history of the disorder in their family. Unlike most other autosomal dominant conditions, in which one altered copy of a gene in each cell is sufficient to cause the disorder, two copies of the NF1 gene must be altered to trigger tumor formation in neurofibromatosis type 1. A mutation in the second copy of the NF1 gene occurs during a person's lifetime in specialized cells surrounding nerves. Almost everyone who is born with one NF1 mutation acquires a second mutation in many cells and develops the tumors characteristic of neurofibromatosis type 1.
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What are the treatments for neurofibromatosis type 1 ?
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These resources address the diagnosis or management of neurofibromatosis type 1: - Gene Review: Gene Review: Neurofibromatosis 1 - Genetic Testing Registry: Neurofibromatosis, type 1 - MedlinePlus Encyclopedia: Neurofibromatosis-1 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) familial male-limited precocious puberty ?
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Familial male-limited precocious puberty is a condition that causes early sexual development in males; females are not affected. Boys with this disorder begin exhibiting the signs of puberty in early childhood, between the ages of 2 and 5. Signs of male puberty include a deepening voice, acne, increased body hair, underarm odor, growth of the penis and testes, and spontaneous erections. Changes in behavior, such as increased aggression and early interest in sex, may also occur. Without treatment, affected boys grow quickly at first, but they stop growing earlier than usual. As a result, they tend to be shorter in adulthood compared with other members of their family.
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How many people are affected by familial male-limited precocious puberty ?
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Familial male-limited precocious puberty is a rare disorder; its prevalence is unknown.
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What are the genetic changes related to familial male-limited precocious puberty ?
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Familial male-limited precocious puberty can be caused by mutations in the LHCGR gene. This gene provides instructions for making a receptor protein called the luteinizing hormone/chorionic gonadotropin receptor. Receptor proteins have specific sites into which certain other proteins, called ligands, fit like keys into locks. Together, ligands and their receptors trigger signals that affect cell development and function. The protein produced from the LHCGR gene acts as a receptor for two ligands: luteinizing hormone and a similar hormone called chorionic gonadotropin. The receptor allows the body to respond appropriately to these hormones. In males, chorionic gonadotropin stimulates the development of cells in the testes called Leydig cells, and luteinizing hormone triggers these cells to produce androgens. Androgens, including testosterone, are the hormones that control male sexual development and reproduction. In females, luteinizing hormone triggers the release of egg cells from the ovaries (ovulation); chorionic gonadotropin is produced during pregnancy and helps maintain conditions necessary for the pregnancy to continue. Certain LHCGR gene mutations result in a receptor protein that is constantly turned on (constitutively activated), even when not attached (bound) to luteinizing hormone or chorionic gonadotropin. In males, the overactive receptor causes excess production of testosterone, which triggers male sexual development and lead to early puberty in affected individuals. The overactive receptor has no apparent effect on females. Approximately 18 percent of individuals with familial male-limited precocious puberty have no identified LHCGR gene mutation. In these individuals, the cause of the disorder is unknown.
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Is familial male-limited precocious puberty inherited ?
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This condition is inherited in an autosomal dominant, male-limited pattern, which means one copy of the altered LHCGR gene in each cell is sufficient to cause the disorder in males. Females with mutations associated with familial male-limited precocious puberty appear to be unaffected. In some cases, an affected male inherits the mutation from either his mother or his father. Other cases result from new mutations in the gene and occur in males with no history of the disorder in their family.
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What are the treatments for familial male-limited precocious puberty ?
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These resources address the diagnosis or management of familial male-limited precocious puberty: - Boston Children's Hospital: Precocious Puberty - Genetic Testing Registry: Gonadotropin-independent familial sexual precocity These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) COG5-congenital disorder of glycosylation ?
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COG5-congenital disorder of glycosylation (COG5-CDG, formerly known as congenital disorder of glycosylation type IIi) is an inherited condition that causes neurological problems and other abnormalities. The pattern and severity of this disorder's signs and symptoms vary among affected individuals. Individuals with COG5-CDG typically develop signs and symptoms of the condition during infancy. These individuals often have weak muscle tone (hypotonia) and delayed development. Other neurological features include moderate to severe intellectual disability, poor coordination, and difficulty walking. Some affected individuals never learn to speak. Other features of COG5-CDG include short stature, an unusually small head size (microcephaly), and distinctive facial features, which can include ears that are set low and rotated backward, a short neck with a low hairline in the back, and a prominent nose. Less commonly, affected individuals can have hearing loss caused by changes in the inner ear (sensorineural hearing loss), vision impairment, damage to the nerves that control bladder function (a condition called neurogenic bladder), liver disease, and joint deformities (contractures).
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How many people are affected by COG5-congenital disorder of glycosylation ?
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COG5-CDG is a very rare disorder; fewer than 10 cases have been described in the medical literature.
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What are the genetic changes related to COG5-congenital disorder of glycosylation ?
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COG5-CDG is caused by mutations in the COG5 gene, which provides instructions for making one piece of a group of proteins known as the conserved oligomeric Golgi (COG) complex. This complex functions in the Golgi apparatus, which is a cellular structure in which newly produced proteins are modified. One process that occurs in the Golgi apparatus is glycosylation, by which sugar molecules (oligosaccharides) are attached to proteins and fats. Glycosylation modifies proteins so they can perform a wider variety of functions. The COG complex takes part in the transport of proteins, including those that perform glycosylation, in the Golgi apparatus. COG5 gene mutations reduce the amount of COG5 protein or eliminate it completely, which disrupts protein transport. This disruption results in abnormal protein glycosylation, which can affect numerous body systems, leading to the signs and symptoms of COG5-CDG. The severity of COG5-CDG is related to the amount of COG5 protein that remains in cells.
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Is COG5-congenital disorder of glycosylation inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for COG5-congenital disorder of glycosylation ?
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These resources address the diagnosis or management of COG5-CDG: - Gene Review: Gene Review: Congenital Disorders of N-Linked Glycosylation Pathway Overview - Genetic Testing Registry: Congenital disorder of glycosylation type 2i These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) MPV17-related hepatocerebral mitochondrial DNA depletion syndrome ?
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MPV17-related hepatocerebral mitochondrial DNA depletion syndrome is an inherited disorder that can cause liver disease and neurological problems. The signs and symptoms of this condition begin in infancy and typically include vomiting, diarrhea, and an inability to grow or gain weight at the expected rate (failure to thrive). Many affected infants have a buildup of a chemical called lactic acid in the body (lactic acidosis) and low blood sugar (hypoglycemia). Within the first weeks of life, infants develop liver disease that quickly progresses to liver failure. The liver is frequently enlarged (hepatomegaly) and liver cells often have a reduced ability to release a digestive fluid called bile (cholestasis). Rarely, affected children develop liver cancer. After the onset of liver disease, many affected infants develop neurological problems, which can include developmental delay, weak muscle tone (hypotonia), and reduced sensation in the limbs (peripheral neuropathy). Individuals with MPV17-related hepatocerebral mitochondrial DNA depletion syndrome typically survive only into infancy or early childhood. MPV17-related hepatocerebral mitochondrial DNA depletion syndrome is most frequently seen in the Navajo population of the southwestern United States. In this population, the condition is known as Navajo neurohepatopathy. People with Navajo neurohepatopathy tend to have a longer life expectancy than those with MPV17-related hepatocerebral mitochondrial DNA depletion syndrome. In addition to the signs and symptoms described above, people with Navajo neurohepatopathy may have problems with sensing pain that can lead to painless bone fractures and self-mutilation of the fingers or toes. Individuals with Navajo neurohepatopathy may lack feeling in the clear front covering of the eye (corneal anesthesia), which can lead to open sores and scarring on the cornea, resulting in impaired vision. The cause of these additional features is unknown.
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How many people are affected by MPV17-related hepatocerebral mitochondrial DNA depletion syndrome ?
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MPV17-related hepatocerebral mitochondrial DNA depletion syndrome is thought to be a rare condition. Approximately 30 cases have been described in the scientific literature, including seven families with Navajo neurohepatopathy. Within the Navajo Nation of the southwestern United States, Navajo neurohepatopathy is estimated to occur in 1 in 1,600 newborns.
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What are the genetic changes related to MPV17-related hepatocerebral mitochondrial DNA depletion syndrome ?
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As the condition name suggests, mutations in the MPV17 gene cause MPV17-related hepatocerebral mitochondrial DNA depletion syndrome. The protein produced from the MPV17 gene is located in the inner membrane of cell structures called mitochondria. Mitochondria are involved in a wide variety of cellular activities, including energy production, chemical signaling, and regulation of cell growth, division, and death. Mitochondria contain their own DNA, known as mitochondrial DNA (mtDNA), which is essential for the normal function of these structures. It is likely that the MPV17 protein is involved in the maintenance of mtDNA. Having an adequate amount of mtDNA is essential for normal energy production within cells. MPV17 gene mutations that cause MPV17-related hepatocerebral mitochondrial DNA depletion syndrome lead to production of a protein with impaired function. One mutation causes all cases of Navajo neurohepatopathy and results in the production of an unstable MPV17 protein that is quickly broken down. A dysfunctional or absent MPV17 protein leads to problems with the maintenance of mtDNA, which can cause a reduction in the amount of mtDNA (known as mitochondrial DNA depletion). Mitochondrial DNA depletion impairs mitochondrial function in many of the body's cells and tissues, particularly the brain, liver, and other tissues that have high energy requirements. Reduced mitochondrial function in the liver and brain lead to the liver failure and neurological dysfunction associated with MPV17-related hepatocerebral mitochondrial DNA depletion syndrome. Researchers suggest that the less mtDNA that is available in cells, the more severe the features of Navajo neurohepatopathy.
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Is MPV17-related hepatocerebral mitochondrial DNA depletion syndrome inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for MPV17-related hepatocerebral mitochondrial DNA depletion syndrome ?
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These resources address the diagnosis or management of MPV17-related hepatocerebral mitochondrial DNA depletion syndrome: - Gene Review: Gene Review: MPV17-Related Hepatocerebral Mitochondrial DNA Depletion Syndrome - Genetic Testing Registry: Navajo neurohepatopathy - The United Mitochondrial Disease Foundation: Treatments and Therapies These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) prekallikrein deficiency ?
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Prekallikrein deficiency is a blood condition that usually causes no health problems. In people with this condition, blood tests show a prolonged activated partial thromboplastin time (PTT), a result that is typically associated with bleeding problems; however, bleeding problems generally do not occur in prekallikrein deficiency. The condition is usually discovered when blood tests are done for other reasons. A few people with prekallikrein deficiency have experienced health problems related to blood clotting such as heart attack, stroke, a clot in the deep veins of the arms or legs (deep vein thrombosis), nosebleeds, or excessive bleeding after surgery. However, these are common problems in the general population, and most affected individuals have other risk factors for developing them, so it is unclear whether their occurrence is related to prekallikrein deficiency.
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How many people are affected by prekallikrein deficiency ?
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The prevalence of prekallikrein deficiency is unknown. Approximately 80 affected individuals in about 30 families have been described in the medical literature. Because prekallikrein deficiency usually does not cause any symptoms, researchers suspect that most people with the condition are never diagnosed.
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What are the genetic changes related to prekallikrein deficiency ?
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Prekallikrein deficiency is caused by mutations in the KLKB1 gene, which provides instructions for making a protein called prekallikrein. This protein, when converted to an active form called plasma kallikrein in the blood, is involved in the early stages of blood clotting. Plasma kallikrein plays a role in a process called the intrinsic coagulation pathway (also called the contact activation pathway). This pathway turns on (activates) proteins that are needed later in the clotting process. Blood clots protect the body after an injury by sealing off damaged blood vessels and preventing further blood loss. The KLKB1 gene mutations that cause prekallikrein deficiency reduce or eliminate functional plasma kallikrein, which likely impairs the intrinsic coagulation pathway. Researchers suggest that this lack (deficiency) of functional plasma kallikrein protein does not generally cause any symptoms because another process called the extrinsic coagulation pathway (also known as the tissue factor pathway) can compensate for the impaired intrinsic coagulation pathway.
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Is prekallikrein deficiency inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for prekallikrein deficiency ?
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These resources address the diagnosis or management of prekallikrein deficiency: - Genetic Testing Registry: Prekallikrein deficiency - Massachusetts General Hospital Laboratory Handbook: Prekallikrein These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) multiple mitochondrial dysfunctions syndrome ?
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Multiple mitochondrial dysfunctions syndrome is characterized by impairment of cellular structures called mitochondria, which are the energy-producing centers of cells. While certain mitochondrial disorders are caused by impairment of a single stage of energy production, individuals with multiple mitochondrial dysfunctions syndrome have reduced function of more than one stage. The signs and symptoms of this severe condition begin early in life, and affected individuals usually do not live past infancy. Affected infants typically have severe brain dysfunction (encephalopathy), which can contribute to weak muscle tone (hypotonia), seizures, and delayed development of mental and movement abilities (psychomotor delay). These infants often have difficulty growing and gaining weight at the expected rate (failure to thrive). Most affected babies have a buildup of a chemical called lactic acid in the body (lactic acidosis), which can be life-threatening. They may also have high levels of a molecule called glycine (hyperglycinemia) or elevated levels of sugar (hyperglycemia) in the blood. Some babies with multiple mitochondrial dysfunctions syndrome have high blood pressure in the blood vessels that connect to the lungs (pulmonary hypertension) or weakening of the heart muscle (cardiomyopathy).
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How many people are affected by multiple mitochondrial dysfunctions syndrome ?
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Multiple mitochondrial dysfunctions syndrome is a rare condition; its prevalence is unknown. It is one of several conditions classified as mitochondrial disorders, which affect an estimated 1 in 5,000 people worldwide.
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What are the genetic changes related to multiple mitochondrial dysfunctions syndrome ?
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Multiple mitochondrial dysfunctions syndrome can be caused by mutations in the NFU1 or BOLA3 gene. The proteins produced from each of these genes appear to be involved in the formation of molecules called iron-sulfur (Fe-S) clusters or in the attachment of these clusters to other proteins. Certain proteins require attachment of Fe-S clusters to function properly. The NFU-1 and BOLA3 proteins play an important role in mitochondria. In these structures, several proteins carry out a series of chemical steps to convert the energy in food into a form that cells can use. Many of the proteins involved in these steps require Fe-S clusters to function, including protein complexes called complex I, complex II, and complex III. Fe-S clusters are also required for another mitochondrial protein to function; this protein is involved in the modification of additional proteins that aid in energy production in mitochondria, including the pyruvate dehydrogenase complex and the alpha-ketoglutarate dehydrogenase complex (also known as the oxoglutarate dehydrogenase complex). This modification is also critical to the function of the glycine cleavage system, a set of proteins that breaks down a protein building block (amino acid) called glycine when levels become too high. Mutations in the NFU1 or BOLA3 gene reduce or eliminate production of the respective protein, which impairs Fe-S cluster formation. Consequently, proteins affected by the presence of Fe-S clusters, including those involved in energy production and glycine breakdown, cannot function normally. Reduced activity of complex I, II, or III, pyruvate dehydrogenase, or alpha-ketoglutarate dehydrogenase leads to potentially fatal lactic acidosis, encephalopathy, and other signs and symptoms of multiple mitochondrial dysfunctions syndrome. In some affected individuals, impairment of the glycine cleavage system leads to a buildup of glycine.
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Is multiple mitochondrial dysfunctions syndrome inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for multiple mitochondrial dysfunctions syndrome ?
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These resources address the diagnosis or management of multiple mitochondrial dysfunctions syndrome: - Gene Review: Gene Review: Mitochondrial Disorders Overview - Genetic Testing Registry: Multiple mitochondrial dysfunctions syndrome 1 - Genetic Testing Registry: Multiple mitochondrial dysfunctions syndrome 2 - Genetic Testing Registry: Multiple mitochondrial dysfunctions syndrome 3 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) Nicolaides-Baraitser syndrome ?
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Nicolaides-Baraitser syndrome is a condition that affects many body systems. Affected individuals can have a wide variety of signs and symptoms, but the most common are sparse scalp hair, small head size (microcephaly), distinct facial features, short stature, prominent finger joints, unusually short fingers and toes (brachydactyly), recurrent seizures (epilepsy), and moderate to severe intellectual disability with impaired language development. In people with Nicolaides-Baraitser syndrome, the sparse scalp hair is often noticeable in infancy. The amount of hair decreases over time, but the growth rate and texture of the hair that is present is normal. Affected adults generally have very little hair. In rare cases, the amount of scalp hair increases over time. As affected individuals age, their eyebrows may become less full, but their eyelashes almost always remain normal. At birth, the hair on the face may be abnormally thick (hypertrichosis) but thins out over time. Most affected individuals grow slowly, resulting in short stature and microcephaly. Sometimes, growth before birth is unusually slow. The characteristic facial features of people with Nicolaides-Baraitser syndrome include a triangular face, deep-set eyes, a thin nasal bridge, wide nostrils, a pointed nasal tip, and a thick lower lip. Many affected individuals have a lack of fat under the skin (subcutaneous fat) of the face, which may cause premature wrinkling. Throughout their bodies, people with Nicolaides-Baraitser syndrome may have pale skin with veins that are visible on the skin surface due to the lack of subcutaneous fat. In people with Nicolaides-Baraitser syndrome, a lack of subcutaneous fat in the hands makes the finger joints appear larger than normal. Over time, the fingertips become broad and oval shaped. Additionally, there is a wide gap between the first and second toes (known as a sandal gap). Most people with Nicolaides-Baraitser syndrome have epilepsy, which often begins in infancy. Affected individuals can experience multiple seizure types, and the seizures can be difficult to control with medication. Almost everyone with Nicolaides-Baraitser syndrome has moderate to severe intellectual disability. Early developmental milestones, such as crawling and walking, are often normally achieved, but further development is limited, and language development is severely impaired. At least one-third of affected individuals never develop speech, while others lose their verbal communication over time. People with this condition are often described as having a happy demeanor and being very friendly, although they can exhibit moments of aggression and temper tantrums. Other signs and symptoms of Nicolaides-Baraitser syndrome include an inflammatory skin disorder called eczema. About half of individuals with Nicolaides-Baraitser syndrome have a soft out-pouching around the belly-button (umbilical hernia) or lower abdomen (inguinal hernia). Some affected individuals have dental abnormalities such as widely spaced teeth, delayed eruption of teeth, and absent teeth (hypodontia). Most affected males have undescended testes (cryptorchidism) and females may have underdeveloped breasts. Nearly half of individuals with Nicolaides-Baraitser syndrome have feeding problems.
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How many people are affected by Nicolaides-Baraitser syndrome ?
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Nicolaides-Baraitser syndrome is likely a rare condition; approximately 75 cases have been reported in the scientific literature.
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What are the genetic changes related to Nicolaides-Baraitser syndrome ?
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Nicolaides-Baraitser syndrome is caused by mutations in the SMARCA2 gene. This gene provides instructions for making one piece (subunit) of a group of similar protein complexes known as SWI/SNF complexes. These complexes regulate gene activity (expression) by a process known as chromatin remodeling. Chromatin is the network of DNA and proteins that packages DNA into chromosomes. The structure of chromatin can be changed (remodeled) to alter how tightly DNA is packaged. Chromatin remodeling is one way gene expression is regulated during development; when DNA is tightly packed, gene expression is lower than when DNA is loosely packed. To provide energy for chromatin remodeling, the SMARCA2 protein uses a molecule called ATP. The SMARCA2 gene mutations that cause Nicolaides-Baraitser syndrome result in the production of an altered protein that interferes with the normal function of the SWI/SNF complexes. These altered proteins are able to form SWI/SNF complexes, but the complexes are nonfunctional. As a result, they cannot participate in chromatin remodeling. Disturbance of this regulatory process alters the activity of many genes, which likely explains the diverse signs and symptoms of Nicolaides-Baraitser syndrome.
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Is Nicolaides-Baraitser syndrome inherited ?
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Nicolaides-Baraitser syndrome follows an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the disorder. All cases of this condition result from new (de novo) mutations in the gene that occur during the formation of reproductive cells (eggs or sperm) or in early embryonic development. These cases occur in people with no history of the disorder in their family.
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What are the treatments for Nicolaides-Baraitser syndrome ?
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These resources address the diagnosis or management of Nicolaides-Baraitser syndrome: - Gene Review: Gene Review: Nicolaides-Baraitser Syndrome - Genetic Testing Registry: Nicolaides-Baraitser syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) adenine phosphoribosyltransferase deficiency ?
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Adenine phosphoribosyltransferase (APRT) deficiency is an inherited condition that affects the kidneys and urinary tract. The most common feature of this condition is recurrent kidney stones; urinary tract stones are also a frequent symptom. Kidney and urinary tract stones can create blockages in the urinary tract, causing pain during urination and difficulty releasing urine. Affected individuals can develop features of this condition anytime from infancy to late adulthood. When the condition appears in infancy, the first sign is usually the presence of tiny grains of reddish-brown material in the baby's diaper caused by the passing of stones. Later, recurrent kidney and urinary tract stones can lead to problems with kidney function beginning as early as mid- to late childhood. Approximately half of individuals with APRT deficiency first experience signs and symptoms of the condition in adulthood. The first features in affected adults are usually kidney stones and related urinary problems. Other signs and symptoms of APRT deficiency caused by kidney and urinary tract stones include fever, urinary tract infection, blood in the urine (hematuria), abdominal cramps, nausea, and vomiting. Without treatment, kidney function can decline, which may lead to end-stage renal disease (ESRD). ESRD is a life-threatening failure of kidney function that occurs when the kidneys are no longer able to filter fluids and waste products from the body effectively. The features of this condition and their severity vary greatly among affected individuals, even among members of the same family. It is estimated that 15 to 20 percent of people with APRT deficiency do not have any signs or symptoms of the condition.
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How many people are affected by adenine phosphoribosyltransferase deficiency ?
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APRT deficiency is estimated to affect 1 in 27,000 people in Japan. The condition is rarer in Europe, where it is thought to affect 1 in 50,000 to 100,000 people. The prevalence of APRT deficiency outside these populations is unknown.
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What are the genetic changes related to adenine phosphoribosyltransferase deficiency ?
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Mutations in the APRT gene cause APRT deficiency. This gene provides instructions for making APRT, an enzyme that helps to convert a DNA building block (nucleotide) called adenine to a molecule called adenosine monophosphate (AMP). This conversion occurs when AMP is needed as a source of energy for cells. APRT gene mutations lead to the production of an abnormal APRT enzyme with reduced function or prevent the production of any enzyme. A lack of functional enzyme impairs the conversion of adenine to AMP. As a result, adenine is converted to another molecule called 2,8-dihydroxyadenine (2,8-DHA). 2,8-DHA crystallizes in urine, forming stones in the kidneys and urinary tract. 2,8-DHA crystals are brownish in color, which explains why affected infants frequently have dark urine stains in their diapers. 2,8-DHA is toxic to kidneys, which may explain the possible decline in kidney function and the progression to ESRD.
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Is adenine phosphoribosyltransferase deficiency inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for adenine phosphoribosyltransferase deficiency ?
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These resources address the diagnosis or management of adenine phosphoribosyltransferase deficiency: - Boston Children's Hospital: Pediatric Kidney Stones in Children - Gene Review: Gene Review: Adenine Phosphoribosyltransferase Deficiency - Genetic Testing Registry: Adenine phosphoribosyltransferase deficiency These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) X-linked chondrodysplasia punctata 2 ?
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X-linked chondrodysplasia punctata 2 is a disorder characterized by bone, skin, and eye abnormalities. It occurs almost exclusively in females. Although the signs and symptoms of this condition vary widely, almost all affected individuals have chondrodysplasia punctata, an abnormality that appears on x-rays as spots (stippling) near the ends of bones and in cartilage. In this form of chondrodysplasia punctata, the stippling typically affects the long bones in the arms and legs, the ribs, the spinal bones (vertebrae), and the cartilage that makes up the windpipe (trachea). The stippling is apparent in infancy but disappears in early childhood. Other skeletal abnormalities seen in people with X-linked chondrodysplasia punctata 2 include shortening of the bones in the upper arms and thighs (rhizomelia) that is often different on the right and left sides, and progressive abnormal curvature of the spine (kyphoscoliosis). As a result of these abnormalities, people with this condition tend to have short stature. Infants with X-linked chondrodysplasia punctata 2 are born with dry, scaly patches of skin (ichthyosis) in a linear or spiral (whorled) pattern. The scaly patches fade over time, leaving abnormally colored blotches of skin without hair (follicular atrophoderma). Most affected individuals also have sparse, coarse hair on their scalps. Most people with X-linked chondrodysplasia punctata 2 have clouding of the lens of the eye (cataracts) from birth or early childhood. Other eye abnormalities that have been associated with this disorder include unusually small eyes (microphthalmia) and small corneas (microcornea). The cornea is the clear front surface of the eye. These eye abnormalities can impair vision. In affected females, X-linked chondrodysplasia punctata 2 is typically associated with normal intelligence and a normal lifespan. However, a much more severe form of the condition has been reported in a small number of males. Affected males have some of the same features as affected females, as well as weak muscle tone (hypotonia), changes in the structure of the brain, moderately to profoundly delayed development, seizures, distinctive facial features, and other birth defects. The health problems associated with X-linked chondrodysplasia punctata 2 are often life-threatening in males.
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How many people are affected by X-linked chondrodysplasia punctata 2 ?
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X-linked chondrodysplasia punctata 2 has been estimated to affect fewer than 1 in 400,000 newborns. However, the disorder may actually be more common than this estimate because it is likely underdiagnosed, particularly in females with mild signs and symptoms. More than 95 percent of cases of X-linked chondrodysplasia punctata 2 occur in females. About a dozen males with the condition have been reported in the scientific literature.
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What are the genetic changes related to X-linked chondrodysplasia punctata 2 ?
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X-linked chondrodysplasia punctata 2 is caused by mutations in the EBP gene. This gene provides instructions for making an enzyme called 3-hydroxysteroid-8,7-isomerase, which is responsible for one of the final steps in the production of cholesterol. Cholesterol is a waxy, fat-like substance that is produced in the body and obtained from foods that come from animals (particularly egg yolks, meat, poultry, fish, and dairy products). Although too much cholesterol is a risk factor for heart disease, this molecule is necessary for normal embryonic development and has important functions both before and after birth. It is a structural component of cell membranes and plays a role in the production of certain hormones and digestive acids. Mutations in the EBP gene reduce the activity of 3-hydroxysteroid-8,7-isomerase, preventing cells from producing enough cholesterol. A shortage of this enzyme also allows potentially toxic byproducts of cholesterol production to build up in the body. The combination of low cholesterol levels and an accumulation of other substances likely disrupts the growth and development of many body systems. It is not known, however, how this disturbance in cholesterol production leads to the specific features of X-linked chondrodysplasia punctata 2.
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Is X-linked chondrodysplasia punctata 2 inherited ?
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This condition is inherited in an X-linked dominant pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In females (who have two X chromosomes), a mutation in one of the two copies of the EBP gene in each cell is sufficient to cause the disorder. Some cells produce a normal amount of 3-hydroxysteroid-8,7-isomerase and other cells produce none. The resulting overall reduction in the amount of this enzyme underlies the signs and symptoms of X-linked chondrodysplasia punctata 2. In males (who have only one X chromosome), a mutation in the EBP gene can result in a total loss of 3-hydroxysteroid-8,7-isomerase. A complete lack of this enzyme is usually lethal in the early stages of development, so few males have been born with X-linked chondrodysplasia punctata 2.
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What are the treatments for X-linked chondrodysplasia punctata 2 ?
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These resources address the diagnosis or management of X-linked chondrodysplasia punctata 2: - Gene Review: Gene Review: Chondrodysplasia Punctata 2, X-Linked - Genetic Testing Registry: Chondrodysplasia punctata 2 X-linked dominant These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) psoriatic arthritis ?
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Psoriatic arthritis is a condition involving joint inflammation (arthritis) that usually occurs in combination with a skin disorder called psoriasis. Psoriasis is a chronic inflammatory condition characterized by patches of red, irritated skin that are often covered by flaky white scales. People with psoriasis may also have changes in their fingernails and toenails, such as nails that become pitted or ridged, crumble, or separate from the nail beds. Signs and symptoms of psoriatic arthritis include stiff, painful joints with redness, heat, and swelling in the surrounding tissues. When the hands and feet are affected, swelling and redness may result in a "sausage-like" appearance of the fingers or toes (dactylitis). In most people with psoriatic arthritis, psoriasis appears before joint problems develop. Psoriasis typically begins during adolescence or young adulthood, and psoriatic arthritis usually occurs between the ages of 30 and 50. However, both conditions may occur at any age. In a small number of cases, psoriatic arthritis develops in the absence of noticeable skin changes. Psoriatic arthritis may be difficult to distinguish from other forms of arthritis, particularly when skin changes are minimal or absent. Nail changes and dactylitis are two features that are characteristic of psoriatic arthritis, although they do not occur in all cases. Psoriatic arthritis is categorized into five types: distal interphalangeal predominant, asymmetric oligoarticular, symmetric polyarthritis, spondylitis, and arthritis mutilans. The distal interphalangeal predominant type affects mainly the ends of the fingers and toes. The distal interphalangeal joints are those closest to the nails. Nail changes are especially frequent with this form of psoriatic arthritis. The asymmetric oligoarticular and symmetric polyarthritis types are the most common forms of psoriatic arthritis. The asymmetric oligoarticular type of psoriatic arthritis involves different joints on each side of the body, while the symmetric polyarthritis form affects the same joints on each side. Any joint in the body may be affected in these forms of the disorder, and symptoms range from mild to severe. Some individuals with psoriatic arthritis have joint involvement that primarily involves spondylitis, which is inflammation in the joints between the vertebrae in the spine. Symptoms of this form of the disorder involve pain and stiffness in the back or neck, and movement is often impaired. Joints in the arms, legs, hands, and feet may also be involved. The most severe and least common type of psoriatic arthritis is called arthritis mutilans. Fewer than 5 percent of individuals with psoriatic arthritis have this form of the disorder. Arthritis mutilans involves severe inflammation that damages the joints in the hands and feet, resulting in deformation and movement problems. Bone loss (osteolysis) at the joints may lead to shortening (telescoping) of the fingers and toes. Neck and back pain may also occur.
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How many people are affected by psoriatic arthritis ?
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Psoriatic arthritis affects an estimated 24 in 10,000 people. Between 5 and 10 percent of people with psoriasis develop psoriatic arthritis, according to most estimates. Some studies suggest a figure as high as 30 percent. Psoriasis itself is a common disorder, affecting approximately 2 to 3 percent of the population worldwide.
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What are the genetic changes related to psoriatic arthritis ?
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The specific cause of psoriatic arthritis is unknown. Its signs and symptoms result from excessive inflammation in and around the joints. Inflammation occurs when the immune system sends signaling molecules and white blood cells to a site of injury or disease to fight microbial invaders and facilitate tissue repair. When this has been accomplished, the body ordinarily stops the inflammatory response to prevent damage to its own cells and tissues. Mechanical stress on the joints, such as occurs in movement, may result in an excessive inflammatory response in people with psoriatic arthritis. The reasons for this excessive inflammatory response are unclear. Researchers have identified changes in several genes that may influence the risk of developing psoriatic arthritis. The most well-studied of these genes belong to a family of genes called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders (such as viruses and bacteria). Each HLA gene has many different normal variations, allowing each person's immune system to react to a wide range of foreign proteins. Variations of several HLA genes seem to affect the risk of developing psoriatic arthritis, as well as the type, severity, and progression of the condition. Variations in several other genes have also been associated with psoriatic arthritis. Many of these genes are thought to play roles in immune system function. However, variations in these genes probably make only a small contribution to the overall risk of developing psoriatic arthritis. Other genetic and environmental factors are also likely to influence a person's chances of developing this disorder.
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Is psoriatic arthritis inherited ?
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This condition has an unknown inheritance pattern. Approximately 40 percent of affected individuals have at least one close family member with psoriasis or psoriatic arthritis.
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What are the treatments for psoriatic arthritis ?
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These resources address the diagnosis or management of psoriatic arthritis: - American Society for Surgery of the Hand - Genetic Testing Registry: Psoriatic arthritis, susceptibility to - The Johns Hopkins Arthritis Center These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) MECP2 duplication syndrome ?
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MECP2 duplication syndrome is a condition that occurs almost exclusively in males and is characterized by moderate to severe intellectual disability. Most people with this condition also have weak muscle tone in infancy, feeding difficulties, poor or absent speech, seizures that may not improve with treatment, or muscle stiffness (spasticity). Individuals with MECP2 duplication syndrome have delayed development of motor skills such as sitting and walking. Some affected individuals experience the loss of previously acquired skills (developmental regression). Approximately one third of people with this condition cannot walk without assistance. Many individuals with MECP2 duplication syndrome have recurrent respiratory tract infections. These respiratory infections are a major cause of death in affected individuals, with almost half succumbing by age 25.
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How many people are affected by MECP2 duplication syndrome ?
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The prevalence of MECP2 duplication syndrome is unknown; approximately 120 affected individuals have been reported in the scientific literature. It is estimated that this condition is responsible for 1 to 2 percent of all cases of intellectual disability caused by changes in the X chromosome.
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What are the genetic changes related to MECP2 duplication syndrome ?
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MECP2 duplication syndrome is caused by a genetic change in which there is an extra copy of the MECP2 gene in each cell. This extra copy of the MECP2 gene is caused by a duplication of genetic material on the long (q) arm of the X chromosome. The size of the duplication varies from 100,000 to 900,000 DNA building blocks (base pairs), also written as 100 to 900 kilobases (kb). The MECP2 gene is always included in this duplication, and other genes may be involved, depending on the size of the duplicated segment. Extra copies of these other genes do not seem to affect the severity of the condition, because people with larger duplications have signs and symptoms that are similar to people with smaller duplications. The MECP2 gene provides instructions for making a protein called MeCP2 that is critical for normal brain function. Researchers believe that this protein has several functions, including regulating other genes in the brain by switching them off when they are not needed. An extra copy of the MECP2 gene leads to the production of excess MeCP2 protein, which is unable to properly regulate the expression of other genes. The misregulation of gene expression in the brain results in abnormal nerve cell (neuronal) function. These neuronal abnormalities cause irregular brain activity, leading to the signs and symptoms of MECP2 duplication syndrome.
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Is MECP2 duplication syndrome inherited ?
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MECP2 duplication syndrome is inherited in an X-linked pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), a duplication of the only copy of the MECP2 gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a duplication of one of the two copies of the gene typically does not cause the disorder. Females usually do not have signs and symptoms of MECP2 duplication syndrome because the X chromosome that contains the duplication may be turned off (inactive) due to a process called X-inactivation. Early in embryonic development in females, one of the two X chromosomes is permanently inactivated in somatic cells (cells other than egg and sperm cells). X-inactivation ensures that females, like males, have only one active copy of the X chromosome in each body cell. Usually X-inactivation occurs randomly, such that each X chromosome is active in about half of the body cells. Sometimes X-inactivation is not random, and one X chromosome is active in more than half of cells. When X-inactivation does not occur randomly, it is called skewed X-inactivation. Research shows that females with an MECP2 gene duplication have skewed X-inactivation, which results in the inactivation of the X chromosome containing the duplication in most cells of the body. This skewed X inactivation ensures that only the chromosome with the normal MECP2 gene is expressed. This skewed X-inactivation is why females with an MECP2 gene duplication typically do not have any features related to the additional genetic material.
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What are the treatments for MECP2 duplication syndrome ?
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These resources address the diagnosis or management of MECP2 duplication syndrome: - Cincinnati Children's Hospital: MECP2-Related Disorders - Cleveland Clinic: Spasticity - Gene Review: Gene Review: MECP2 Duplication Syndrome - Genetic Testing Registry: MECP2 duplication syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) Darier disease ?
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Darier disease is a skin condition characterized by wart-like blemishes on the body. The blemishes are usually yellowish in color, hard to the touch, mildly greasy, and can emit a strong odor. The most common sites for blemishes are the scalp, forehead, upper arms, chest, back, knees, elbows, and behind the ear. The mucous membranes can also be affected, with blemishes on the roof of the mouth (palate), tongue, inside of the cheek, gums, and throat. Other features of Darier disease include nail abnormalities, such as red and white streaks in the nails with an irregular texture, and small pits in the palms of the hands and soles of the feet. The wart-like blemishes characteristic of Darier disease usually appear in late childhood to early adulthood. The severity of the disease varies over time; affected people experience flare-ups alternating with periods when they have fewer blemishes. The appearance of the blemishes is influenced by environmental factors. Most people with Darier disease will develop more blemishes during the summertime when they are exposed to heat and humidity. UV light; minor injury or friction, such as rubbing or scratching; and ingestion of certain medications can also cause an increase in blemishes. On occasion, people with Darier disease may have neurological disorders such as mild intellectual disability, epilepsy, and depression. Learning and behavior difficulties have also been reported in people with Darier disease. Researchers do not know if these conditions, which are common in the general population, are associated with the genetic changes that cause Darier disease, or if they are coincidental. Some researchers believe that behavioral problems might be linked to the social stigma experienced by people with numerous skin blemishes. A form of Darier disease known as the linear or segmental form is characterized by blemishes on localized areas of the skin. The blemishes are not as widespread as they are in typical Darier disease. Some people with the linear form of this condition have the nail abnormalities that are seen in people with classic Darier disease, but these abnormalities occur only on one side of the body.
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How many people are affected by Darier disease ?
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The worldwide prevalence of Darier disease is unknown. The prevalence of Darier disease is estimated to be 1 in 30,000 people in Scotland, 1 in 36,000 people in northern England, and 1 in 100,000 people in Denmark.
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What are the genetic changes related to Darier disease ?
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Mutations in the ATP2A2 gene cause Darier disease. The ATP2A2 gene provides instructions for producing an enzyme abbreviated as SERCA2. This enzyme acts as a pump that helps control the level of positively charged calcium atoms (calcium ions) inside cells, particularly in the endoplasmic reticulum and the sarcoplasmic reticulum. The endoplasmic reticulum is a structure inside the cell that is involved in protein processing and transport. The sarcoplasmic reticulum is a structure in muscle cells that assists with muscle contraction and relaxation by releasing and storing calcium ions. Calcium ions act as signals for a large number of activities that are important for the normal development and function of cells. SERCA2 allows calcium ions to pass into and out of the cell in response to cell signals. Mutations in the ATP2A2 gene result in insufficient amounts of functional SERCA2 enzyme. A lack of SERCA2 enzyme reduces calcium levels in the endoplasmic reticulum, causing it to become dysfunctional. SERCA2 is expressed throughout the body; it is not clear why changes in this enzyme affect only the skin. Some researchers note that skin cells are the only cell types expressing SERCA2 that do not have a "back-up" enzyme for calcium transport. This dependence on the SERCA2 enzyme may make skin cells particularly vulnerable to changes in this enzyme. The linear form of Darier disease is caused by ATP2A2 gene mutations that are acquired during a person's lifetime and are present only in certain cells. These changes are called somatic mutations and are not inherited. There have been no known cases of people with the linear form of Darier disease passing it on to their children.
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Is Darier disease inherited ?
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This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family. The linear form of Darier disease is generally not inherited but arises from mutations in the body's cells that occur after conception. These alterations are called somatic mutations.
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What are the treatments for Darier disease ?
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These resources address the diagnosis or management of Darier disease: - Genetic Testing Registry: Keratosis follicularis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) X-linked sideroblastic anemia ?
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X-linked sideroblastic anemia is an inherited disorder that prevents developing red blood cells (erythroblasts) from making enough hemoglobin, which is the protein that carries oxygen in the blood. People with X-linked sideroblastic anemia have mature red blood cells that are smaller than normal (microcytic) and appear pale (hypochromic) because of the shortage of hemoglobin. This disorder also leads to an abnormal accumulation of iron in red blood cells. The iron-loaded erythroblasts, which are present in bone marrow, are called ring sideroblasts. These abnormal cells give the condition its name. The signs and symptoms of X-linked sideroblastic anemia result from a combination of reduced hemoglobin and an overload of iron. They range from mild to severe and most often appear in young adulthood. Common features include fatigue, dizziness, a rapid heartbeat, pale skin, and an enlarged liver and spleen (hepatosplenomegaly). Over time, severe medical problems such as heart disease and liver damage (cirrhosis) can result from the buildup of excess iron in these organs.
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How many people are affected by X-linked sideroblastic anemia ?
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This form of anemia is uncommon. However, researchers believe that it may not be as rare as they once thought. Increased awareness of the disease has led to more frequent diagnoses.
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What are the genetic changes related to X-linked sideroblastic anemia ?
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Mutations in the ALAS2 gene cause X-linked sideroblastic anemia. The ALAS2 gene provides instructions for making an enzyme called erythroid ALA-synthase, which plays a critical role in the production of heme (a component of the hemoglobin protein) in bone marrow. ALAS2 mutations impair the activity of erythroid ALA-synthase, which disrupts normal heme production and prevents erythroblasts from making enough hemoglobin. Because almost all of the iron transported into erythroblasts is normally incorporated into heme, the reduced production of heme leads to a buildup of excess iron in these cells. Additionally, the body attempts to compensate for the hemoglobin shortage by absorbing more iron from the diet. This buildup of excess iron damages the body's organs. Low hemoglobin levels and the resulting accumulation of iron in the body's organs lead to the characteristic features of X-linked sideroblastic anemia. People who have a mutation in another gene, HFE, along with a mutation in the ALAS2 gene may experience a more severe form of X-linked sideroblastic anemia. In this uncommon situation, the combined effect of these two mutations can lead to a more serious iron overload. Mutations in the HFE gene alone can increase the absorption of iron from the diet and result in hemochromatosis, which is another type of iron overload disorder.
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Is X-linked sideroblastic anemia inherited ?
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This condition is inherited in an X-linked recessive pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. Carriers of an ALAS2 mutation can pass on the mutated gene, but most do not develop any symptoms associated with X-linked sideroblastic anemia. However, carriers may have abnormally small, pale red blood cells and related changes that can be detected with a blood test.
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What are the treatments for X-linked sideroblastic anemia ?
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These resources address the diagnosis or management of X-linked sideroblastic anemia: - Genetic Testing Registry: Hereditary sideroblastic anemia - MedlinePlus Encyclopedia: Anemia These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) Northern epilepsy ?
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Northern epilepsy is a genetic condition that causes recurrent seizures (epilepsy) beginning in childhood, usually between ages 5 and 10. Seizures are often the generalized tonic-clonic type, which involve muscle rigidity, convulsions, and loss of consciousness. These seizures typically last less than 5 minutes but can last up to 15 minutes. Some people with Northern epilepsy also experience partial seizures, which do not cause a loss of consciousness. The seizures occur approximately one to two times per month until adolescence; then the frequency decreases to about four to six times per year by early adulthood. By middle age, seizures become even less frequent. Two to 5 years after the start of seizures, people with Northern epilepsy begin to experience a decline in intellectual function, which can result in mild intellectual disability. Problems with coordination usually begin in young adulthood and lead to clumsiness and difficulty with fine motor activities such as writing, using eating utensils, and fastening buttons. During this time, affected individuals often begin to develop balance problems and they walk slowly with short, wide steps. These intellectual and movement problems worsen over time. A loss of sharp vision (reduced visual acuity) may also occur in early to mid-adulthood. Individuals with Northern epilepsy often live into late adulthood, but depending on the severity of the intellectual disability and movement impairments, they may require assistance with tasks of everyday living. Northern epilepsy is one of a group of disorders known as neuronal ceroid lipofuscinoses (NCLs), which are also known as Batten disease. These disorders affect the nervous system and typically cause progressive problems with vision, movement, and thinking ability. The different types of NCLs are distinguished by the age at which signs and symptoms first appear. Northern epilepsy is the mildest form of NCL.
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How many people are affected by Northern epilepsy ?
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Northern epilepsy appears to affect only individuals of Finnish ancestry, particularly those from the Kainuu region of northern Finland. Approximately 1 in 10,000 individuals in this region have the condition.
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What are the genetic changes related to Northern epilepsy ?
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Mutations in the CLN8 gene cause Northern epilepsy. The CLN8 gene provides instructions for making a protein whose function is not well understood. The CLN8 protein is thought to play a role in transporting materials in and out of a cell structure called the endoplasmic reticulum. The endoplasmic reticulum is involved in protein production, processing, and transport. Based on the structure of the CLN8 protein, it may also help regulate the levels of fats (lipids) in cells. A single CLN8 gene mutation has been identified to cause Northern epilepsy. Nearly all affected individuals have this mutation in both copies of the CLN8 gene in each cell. The effects of this mutation on protein function are unclear. Unlike other forms of NCL that result in the accumulation of large amounts of fatty substances called lipopigments in cells, contributing to cell death, Northern epilepsy is associated with very little lipopigment buildup. People with Northern epilepsy do have mild brain abnormalities resulting from cell death, but the cause of this brain cell death is unknown. It is also unclear how changes in the CLN8 protein and a loss of brain cells cause the neurological problems associated with Northern epilepsy.
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Is Northern epilepsy inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for Northern epilepsy ?
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These resources address the diagnosis or management of Northern epilepsy: - Gene Review: Gene Review: Neuronal Ceroid-Lipofuscinoses - Genetic Testing Registry: Ceroid lipofuscinosis, neuronal, 8, northern epilepsy variant These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) familial cold autoinflammatory syndrome ?
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Familial cold autoinflammatory syndrome is a condition that causes episodes of fever, skin rash, and joint pain after exposure to cold temperatures. These episodes usually begin in infancy and occur throughout life. People with this condition usually experience symptoms after cold exposure of an hour or more, although in some individuals only a few minutes of exposure is required. Symptoms may be delayed for up to a few hours after the cold exposure. Episodes last an average of 12 hours, but may continue for up to 3 days. In people with familial cold autoinflammatory syndrome, the most common symptom that occurs during an episode is an itchy or burning rash. The rash usually begins on the face or extremities and spreads to the rest of the body. Occasionally swelling in the extremities may occur. In addition to the skin rash, episodes are characterized by fever, chills, and joint pain, most often affecting the hands, knees, and ankles. Redness in the whites of the eye (conjunctivitis), sweating, drowsiness, headache, thirst, and nausea may also occur during an episode of this disorder.
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How many people are affected by familial cold autoinflammatory syndrome ?
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Familial cold autoinflammatory syndrome is a very rare condition, believed to have a prevalence of less than 1 per million people.
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What are the genetic changes related to familial cold autoinflammatory syndrome ?
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Mutations in the NLRP3 and NLRP12 genes cause familial cold autoinflammatory syndrome. The NLRP3 gene (also known as CIAS1) provides instructions for making a protein called cryopyrin, and the NLRP12 gene provides instructions for making the protein monarch-1. Cryopyrin and monarch-1 belong to a family of proteins called nucleotide-binding domain and leucine-rich repeat containing (NLR) proteins. These proteins are involved in the immune system, helping to regulate the process of inflammation. Inflammation occurs when the immune system sends signaling molecules and white blood cells to a site of injury or disease to fight microbial invaders and facilitate tissue repair. When this has been accomplished, the body stops (inhibits) the inflammatory response to prevent damage to its own cells and tissues. Cryopyrin is involved in the assembly of a molecular complex called an inflammasome, which helps start the inflammatory process. Mutations in the NLRP3 gene result in a hyperactive cryopyrin protein that inappropriately triggers an inflammatory response. Monarch-1 is involved in the inhibition of the inflammatory response. Mutations in the NLRP12 gene appear to reduce the ability of the monarch-1 protein to inhibit inflammation. Impairment of the body's mechanisms for controlling inflammation results in the episodes of skin rash, fever, and joint pain seen in familial cold autoinflammatory syndrome. It is unclear why episodes are triggered by cold exposure in this disorder.
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Is familial cold autoinflammatory syndrome inherited ?
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This condition is inherited in an autosomal dominant pattern from an affected parent; one copy of the altered gene in each cell is sufficient to cause the disorder.
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What are the treatments for familial cold autoinflammatory syndrome ?
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These resources address the diagnosis or management of familial cold autoinflammatory syndrome: - Genetic Testing Registry: Familial cold autoinflammatory syndrome 2 - Genetic Testing Registry: Familial cold urticaria These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) Hutchinson-Gilford progeria syndrome ?
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Hutchinson-Gilford progeria syndrome is a genetic condition characterized by the dramatic, rapid appearance of aging beginning in childhood. Affected children typically look normal at birth and in early infancy, but then grow more slowly than other children and do not gain weight at the expected rate (failure to thrive). They develop a characteristic facial appearance including prominent eyes, a thin nose with a beaked tip, thin lips, a small chin, and protruding ears. Hutchinson-Gilford progeria syndrome also causes hair loss (alopecia), aged-looking skin, joint abnormalities, and a loss of fat under the skin (subcutaneous fat). This condition does not disrupt intellectual development or the development of motor skills such as sitting, standing, and walking. People with Hutchinson-Gilford progeria syndrome experience severe hardening of the arteries (arteriosclerosis) beginning in childhood. This condition greatly increases the chances of having a heart attack or stroke at a young age. These serious complications can worsen over time and are life-threatening for affected individuals.
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How many people are affected by Hutchinson-Gilford progeria syndrome ?
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This condition is very rare; it is reported to occur in 1 in 4 million newborns worldwide. More than 130 cases have been reported in the scientific literature since the condition was first described in 1886.
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