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genetic changes | What are the genetic changes related to alpha thalassemia ? | Alpha thalassemia typically results from deletions involving the HBA1 and HBA2 genes. Both of these genes provide instructions for making a protein called alpha-globin, which is a component (subunit) of hemoglobin. People have two copies of the HBA1 gene and two copies of the HBA2 gene in each cell. Each copy is called an allele. For each gene, one allele is inherited from a person's father, and the other is inherited from a person's mother. As a result, there are four alleles that produce alpha-globin. The different types of alpha thalassemia result from the loss of some or all of these alleles. Hb Bart syndrome, the most severe form of alpha thalassemia, results from the loss of all four alpha-globin alleles. HbH disease is caused by a loss of three of the four alpha-globin alleles. In these two conditions, a shortage of alpha-globin prevents cells from making normal hemoglobin. Instead, cells produce abnormal forms of hemoglobin called hemoglobin Bart (Hb Bart) or hemoglobin H (HbH). These abnormal hemoglobin molecules cannot effectively carry oxygen to the body's tissues. The substitution of Hb Bart or HbH for normal hemoglobin causes anemia and the other serious health problems associated with alpha thalassemia. Two additional variants of alpha thalassemia are related to a reduced amount of alpha-globin. Because cells still produce some normal hemoglobin, these variants tend to cause few or no health problems. A loss of two of the four alpha-globin alleles results in alpha thalassemia trait. People with alpha thalassemia trait may have unusually small, pale red blood cells and mild anemia. A loss of one alpha-globin allele is found in alpha thalassemia silent carriers. These individuals typically have no thalassemia-related signs or symptoms. |
inheritance | Is alpha thalassemia inherited ? | The inheritance of alpha thalassemia is complex. Each person inherits two alpha-globin alleles from each parent. If both parents are missing at least one alpha-globin allele, their children are at risk of having Hb Bart syndrome, HbH disease, or alpha thalassemia trait. The precise risk depends on how many alleles are missing and which combination of the HBA1 and HBA2 genes is affected. |
treatment | What are the treatments for alpha thalassemia ? | These resources address the diagnosis or management of alpha thalassemia: - Gene Review: Gene Review: Alpha-Thalassemia - Genetic Testing Registry: alpha Thalassemia - MedlinePlus Encyclopedia: Thalassemia - University of California, San Francisco Fetal Treatment Center: Stem Cell Treatments 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 |
information | What is (are) KBG syndrome ? | KBG syndrome is a rare disorder that affects several body systems. "KBG" represents the surname initials of the first families diagnosed with the disorder. Common signs and symptoms in individuals with this condition include unusual facial features, skeletal abnormalities, and intellectual disability. A characteristic feature of KBG syndrome is unusually large upper front teeth (macrodontia). Other distinctive facial features include a wide, short skull (brachycephaly), a triangular face shape, widely spaced eyes (hypertelorism), wide eyebrows that may grow together in the middle (synophrys), a prominent nasal bridge, a long space between the nose and upper lip (philtrum), and a thin upper lip. A common skeletal abnormality in people with KBG syndrome is slowed mineralization of bones (delayed bone age); for example, an affected 3-year-old child may have bones more typical of a child of 2. In addition, affected individuals can have abnormalities of the bones of the spine (vertebrae) and ribs. They can also have abnormalities of the bones of the hands, including unusually short or curved fifth (pinky) fingers (brachydactyly or clinodactyly, respectively). Most affected individuals are shorter than average from birth. Development of mental and movement abilities is also delayed in KBG syndrome. Most affected individuals learn to speak and walk later than normal and have mild to moderate intellectual disability. Some people with this condition have behavioral or emotional problems, such as hyperactivity or anxiety. Less common features of KBG syndrome include hearing loss, seizures, and heart defects. |
frequency | How many people are affected by KBG syndrome ? | KBG syndrome is a rare disorder that has been reported in around 60 individuals. For unknown reasons, males are affected more often than females. Doctors think the disorder is underdiagnosed because the signs and symptoms can be mild and may be attributed to other disorders. |
genetic changes | What are the genetic changes related to KBG syndrome ? | KBG syndrome is caused by mutations in the ANKRD11 gene. The protein produced from this gene enables other proteins to interact with each other and helps control gene activity. The ANKRD11 protein is found in nerve cells (neurons) in the brain. It plays a role in the proper development of the brain and may be involved in the ability of neurons to change and adapt over time (plasticity), which is important for learning and memory. ANKRD11 may function in other cells in the body and appears to be involved in normal bone development. Most of the ANKRD11 gene mutations involved in KBG syndrome lead to an abnormally short ANKRD11 protein, which likely has little or no function. Reduction of this protein's function is thought to underlie the signs and symptoms of the condition. Because ANKRD11 is thought to play an important role in neurons and brain development, researchers speculate that a partial loss of its function may lead to developmental delay and intellectual disability in KBG syndrome. However, the mechanism is not fully known. It is also unclear how loss of ANKRD11 function leads to the skeletal features of the condition. |
inheritance | Is KBG syndrome inherited ? | 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. |
treatment | What are the treatments for KBG syndrome ? | These resources address the diagnosis or management of KBG syndrome: - Genetic Testing Registry: KBG 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 |
information | What is (are) Greenberg dysplasia ? | Greenberg dysplasia is a severe condition characterized by specific bone abnormalities in the developing fetus. This condition is fatal before birth. The bones of affected individuals do not develop properly, causing a distinctive spotted appearance called moth-eaten bone, which is visible on x-ray images. In addition, the bones have abnormal calcium deposits (ectopic calcification). Affected individuals have extremely short bones in the arms and legs and abnormally flat vertebrae (platyspondyly). Other skeletal abnormalities may include short ribs and extra fingers (polydactyly). In addition, affected fetuses have extensive swelling of the body caused by fluid accumulation (hydrops fetalis). Greenberg dysplasia is also called hydrops-ectopic calcification-moth-eaten skeletal dysplasia (HEM), which reflects the condition's most common features. |
frequency | How many people are affected by Greenberg dysplasia ? | Greenberg dysplasia is a very rare condition. Approximately ten cases have been reported in the scientific literature. |
genetic changes | What are the genetic changes related to Greenberg dysplasia ? | Mutations in the LBR gene cause Greenberg dysplasia. This gene provides instructions for making a protein called the lamin B receptor. One region of this protein, called the sterol reductase domain, plays an important role in the production (synthesis) of cholesterol. Cholesterol is a type of fat that is produced in the body and obtained from foods that come from animals: eggs, meat, fish, and dairy products. Cholesterol is necessary for normal embryonic development and has important functions both before and after birth. Cholesterol is an important component of cell membranes and the protective substance covering nerve cells (myelin). Additionally, cholesterol plays a role in the production of certain hormones and digestive acids. During cholesterol synthesis, the sterol reductase function of the lamin B receptor allows the protein to perform one of several steps that convert a molecule called lanosterol to cholesterol. LBR gene mutations involved in Greenberg dysplasia lead to loss of the sterol reductase function of the lamin B receptor, and research suggests that this loss causes the condition. Absence of the sterol reductase function disrupts the normal synthesis of cholesterol within cells. This absence may also allow potentially toxic byproducts of cholesterol synthesis to build up in the body's tissues. Researchers suspect that low cholesterol levels or an accumulation of other substances disrupts the growth and development of many parts of the body. It is not known, however, how a disturbance of cholesterol synthesis leads to the specific features of Greenberg dysplasia. |
inheritance | Is Greenberg dysplasia inherited ? | 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. |
treatment | What are the treatments for Greenberg dysplasia ? | These resources address the diagnosis or management of Greenberg dysplasia: - Genetic Testing Registry: Greenberg dysplasia - Lurie Children's Hospital of Chicago: Fetal Skeletal Dysplasia 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 |
information | What is (are) familial porencephaly ? | Familial porencephaly is part of a group of conditions called the COL4A1-related disorders. The conditions in this group have a range of signs and symptoms that involve fragile blood vessels. In familial porencephaly, fluid-filled cysts develop in the brain (porencephaly) during fetal development or soon after birth. These cysts typically occur in only one side of the brain and vary in size. The cysts are thought to be the result of bleeding within the brain (hemorrhagic stroke). People with this condition also have leukoencephalopathy, which is a change in a type of brain tissue called white matter that can be seen with magnetic resonance imaging (MRI). During infancy, people with familial porencephaly typically have paralysis affecting one side of the body (infantile hemiplegia). Affected individuals may also have recurrent seizures (epilepsy), migraine headaches, speech problems, intellectual disability, and uncontrolled muscle tensing (dystonia). Some people are severely affected, and others may have no symptoms related to the brain cysts. |
frequency | How many people are affected by familial porencephaly ? | Familial porencephaly is a rare condition, although the exact prevalence is unknown. At least eight affected families have been described in the scientific literature. |
genetic changes | What are the genetic changes related to familial porencephaly ? | Mutations in the COL4A1 gene cause familial porencephaly. The COL4A1 gene provides instructions for making one component of a protein called type IV collagen. Type IV collagen molecules attach to each other to form complex protein networks. These protein networks are the main components of basement membranes, which are thin sheet-like structures that separate and support cells in many tissues. Type IV collagen networks play an important role in the basement membranes in virtually all tissues throughout the body, particularly the basement membranes surrounding the body's blood vessels (vasculature). The COL4A1 gene mutations that cause familial porencephaly result in the production of a protein that disrupts the structure of type IV collagen. As a result, type IV collagen molecules cannot attach to each other to form the protein networks in basement membranes. Basement membranes without normal type IV collagen are unstable, leading to weakening of the tissues that they surround. In people with familial porencephaly, the vasculature in the brain weakens, which can lead to blood vessel breakage and hemorrhagic stroke. Bleeding within the brain is followed by the formation of fluid-filled cysts characteristic of this condition. It is thought that the pressure and stress on the head during birth contributes to vessel breakage in people with this condition; however in some individuals, bleeding in the brain can occur before birth. |
inheritance | Is familial porencephaly inherited ? | 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. |
treatment | What are the treatments for familial porencephaly ? | These resources address the diagnosis or management of familial porencephaly: - Gene Review: Gene Review: COL4A1-Related Disorders - Genetic Testing Registry: Familial porencephaly 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 |
information | What is (are) psoriatic arthritis ? | 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. |
frequency | How many people are affected by psoriatic arthritis ? | 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. |
genetic changes | What are the genetic changes related to psoriatic arthritis ? | 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. |
inheritance | Is psoriatic arthritis inherited ? | 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. |
treatment | What are the treatments for psoriatic arthritis ? | 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 |
information | What is (are) carbamoyl phosphate synthetase I deficiency ? | Carbamoyl phosphate synthetase I deficiency is an inherited disorder that causes ammonia to accumulate in the blood (hyperammonemia). Ammonia, which is formed when proteins are broken down in the body, is toxic if the levels become too high. The brain is especially sensitive to the effects of excess ammonia. In the first few days of life, infants with carbamoyl phosphate synthetase I deficiency typically exhibit the effects of hyperammonemia, which may include unusual sleepiness, poorly regulated breathing rate or body temperature, unwillingness to feed, vomiting after feeding, unusual body movements, seizures, or coma. Affected individuals who survive the newborn period may experience recurrence of these symptoms if diet is not carefully managed or if they experience infections or other stressors. They may also have delayed development and intellectual disability. In some people with carbamoyl phosphate synthetase I deficiency, signs and symptoms may be less severe and appear later in life. |
frequency | How many people are affected by carbamoyl phosphate synthetase I deficiency ? | Carbamoyl phosphate synthetase I deficiency is a rare disorder; its overall incidence is unknown. Researchers in Japan have estimated that it occurs in 1 in 800,000 newborns in that country. |
genetic changes | What are the genetic changes related to carbamoyl phosphate synthetase I deficiency ? | Mutations in the CPS1 gene cause carbamoyl phosphate synthetase I deficiency. The CPS1 gene provides instructions for making the enzyme carbamoyl phosphate synthetase I. This enzyme participates in the urea cycle, which is a sequence of biochemical reactions that occurs in liver cells. The urea cycle processes excess nitrogen, generated when protein is broken down by the body, to make a compound called urea that is excreted by the kidneys. The specific role of the carbamoyl phosphate synthetase I enzyme is to control the first step of the urea cycle, a reaction in which excess nitrogen compounds are incorporated into the cycle to be processed. Carbamoyl phosphate synthetase I deficiency belongs to a class of genetic diseases called urea cycle disorders. In this condition, the carbamoyl phosphate synthetase I enzyme is at low levels (deficient) or absent, and the urea cycle cannot proceed normally. As a result, nitrogen accumulates in the bloodstream in the form of toxic ammonia instead of being converted to less toxic urea and excreted. Ammonia is especially damaging to the brain, and excess ammonia causes neurological problems and other signs and symptoms of carbamoyl phosphate synthetase I deficiency. |
inheritance | Is carbamoyl phosphate synthetase I deficiency inherited ? | 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. |
treatment | What are the treatments for carbamoyl phosphate synthetase I deficiency ? | These resources address the diagnosis or management of carbamoyl phosphate synthetase I deficiency: - Baby's First Test - Gene Review: Gene Review: Urea Cycle Disorders Overview - Genetic Testing Registry: Congenital hyperammonemia, type I - MedlinePlus Encyclopedia: Hereditary Urea Cycle Abnormality 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 |
information | What is (are) rheumatoid arthritis ? | Rheumatoid arthritis is a disease that causes chronic abnormal inflammation, primarily affecting the joints. The most common signs and symptoms are pain, swelling, and stiffness of the joints. Small joints in the hands and feet are involved most often, although larger joints (such as the shoulders, hips, and knees) may become involved later in the disease. Joints are typically affected in a symmetrical pattern; for example, if joints in the hand are affected, both hands tend to be involved. People with rheumatoid arthritis often report that their joint pain and stiffness is worse when getting out of bed in the morning or after a long rest. Rheumatoid arthritis can also cause inflammation of other tissues and organs, including the eyes, lungs, and blood vessels. Additional signs and symptoms of the condition can include a loss of energy, a low fever, weight loss, and a shortage of red blood cells (anemia). Some affected individuals develop rheumatoid nodules, which are firm lumps of noncancerous tissue that can grow under the skin and elsewhere in the body. The signs and symptoms of rheumatoid arthritis usually appear in mid- to late adulthood. Many affected people have episodes of symptoms (flares) followed by periods with no symptoms (remissions) for the rest of their lives. In severe cases, affected individuals have continuous health problems related to the disease for many years. The abnormal inflammation can lead to severe joint damage, which limits movement and can cause significant disability. |
frequency | How many people are affected by rheumatoid arthritis ? | Rheumatoid arthritis affects about 1.3 million adults in the United States. Worldwide, it is estimated to occur in up to 1 percent of the population. The disease is two to three times more common in women than in men, which may be related to hormonal factors. |
genetic changes | What are the genetic changes related to rheumatoid arthritis ? | Rheumatoid arthritis probably results from a combination of genetic and environmental factors, many of which are unknown. Rheumatoid arthritis is classified as an autoimmune disorder, one of a large group of conditions that occur when the immune system attacks the body's own tissues and organs. In people with rheumatoid arthritis, the immune system triggers abnormal inflammation in the membrane that lines the joints (the synovium). When the synovium is inflamed, it causes pain, swelling, and stiffness of the joint. In severe cases, the inflammation also affects the bone, cartilage, and other tissues within the joint, causing more serious damage. Abnormal immune reactions also underlie the features of rheumatoid arthritis affecting other parts of the body. Variations in dozens of genes have been studied as risk factors for rheumatoid arthritis. Most of these genes are known or suspected to be involved in immune system function. The most significant genetic risk factors for rheumatoid arthritis are variations in human leukocyte antigen (HLA) genes, especially the HLA-DRB1 gene. The proteins produced from HLA genes help the immune system distinguish the body's own proteins from proteins made by foreign invaders (such as viruses and bacteria). Changes in other genes appear to have a smaller impact on a person's overall risk of developing the condition. Other, nongenetic factors are also believed to play a role in rheumatoid arthritis. These factors may trigger the condition in people who are at risk, although the mechanism is unclear. Potential triggers include changes in sex hormones (particularly in women), occupational exposure to certain kinds of dust or fibers, and viral or bacterial infections. Long-term smoking is a well-established risk factor for developing rheumatoid arthritis; it is also associated with more severe signs and symptoms in people who have the disease. |
inheritance | Is rheumatoid arthritis inherited ? | The inheritance pattern of rheumatoid arthritis is unclear because many genetic and environmental factors appear to be involved. However, having a close relative with rheumatoid arthritis likely increases a person's risk of developing the condition. |
treatment | What are the treatments for rheumatoid arthritis ? | These resources address the diagnosis or management of rheumatoid arthritis: - American College of Rheumatology: ACR-Endorsed Criteria for Rheumatic Diseases - American College of Rheumatology: Treatment for Rheumatic Diseases - Genetic Testing Registry: Rheumatoid arthritis 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 |
information | What is (are) generalized arterial calcification of infancy ? | Generalized arterial calcification of infancy (GACI) is a disorder affecting the circulatory system that becomes apparent before birth or within the first few months of life. It is characterized by abnormal accumulation of the mineral calcium (calcification) in the walls of the blood vessels that carry blood from the heart to the rest of the body (the arteries). This calcification often occurs along with thickening of the lining of the arterial walls (the intima). These changes lead to narrowing (stenosis) and stiffness of the arteries, which forces the heart to work harder to pump blood. As a result, heart failure may develop in affected individuals, with signs and symptoms including difficulty breathing, accumulation of fluid (edema) in the extremities, a bluish appearance of the skin or lips (cyanosis), severe high blood pressure (hypertension), and an enlarged heart (cardiomegaly). People with GACI may also have calcification in other organs and tissues, particularly around the joints. In addition, they may have hearing loss or softening and weakening of the bones (rickets). Some individuals with GACI also develop features similar to those of another disorder called pseudoxanthoma elasticum (PXE). PXE is characterized by the accumulation of calcium and other minerals (mineralization) in elastic fibers, which are a component of connective tissue. Connective tissue provides strength and flexibility to structures throughout the body. Features characteristic of PXE that also occur in GACI include yellowish bumps called papules on the underarms and other areas of skin that touch when a joint bends (flexor areas); and abnormalities called angioid streaks affecting tissue at the back of the eye, which can be detected during an eye examination. As a result of the cardiovascular problems associated with GACI, individuals with this condition often do not survive past infancy, with death typically caused by a heart attack or stroke. However, affected individuals who survive their first six months, known as the critical period, can live into adolescence or early adulthood. |
frequency | How many people are affected by generalized arterial calcification of infancy ? | The prevalence of GACI has been estimated to be about 1 in 391,000. At least 200 affected individuals have been described in the medical literature. |
genetic changes | What are the genetic changes related to generalized arterial calcification of infancy ? | In about two-thirds of cases, GACI is caused by mutations in the ENPP1 gene. This gene provides instructions for making a protein that helps break down a molecule called adenosine triphosphate (ATP), specifically when it is found outside the cell (extracellular). Extracellular ATP is quickly broken down into other molecules called adenosine monophosphate (AMP) and pyrophosphate. Pyrophosphate is important in controlling calcification and other mineralization in the body. Mutations in the ENPP1 gene are thought to result in reduced availability of pyrophosphate, leading to excessive calcification in the body and causing the signs and symptoms of GACI. GACI can also be caused by mutations in the ABCC6 gene. This gene provides instructions for making a protein called MRP6, also known as the ABCC6 protein. This protein is found primarily in the liver and kidneys, with small amounts in other tissues such as the skin, stomach, blood vessels, and eyes. MRP6 is thought to transport certain substances across the cell membrane; however, the substances have not been identified. Some studies suggest that the MRP6 protein stimulates the release of ATP from cells through an unknown mechanism, allowing it to be broken down into AMP and pyrophosphate and helping to control deposition of calcium and other minerals in the body as described above. Other studies suggest that a substance transported by MRP6 is involved in the breakdown of ATP. This unidentified substance is thought to help prevent mineralization of tissues. Mutations in the ABCC6 gene lead to an absent or nonfunctional MRP6 protein. It is unclear how a lack of properly functioning MRP6 protein leads to GACI. This shortage may impair the release of ATP from cells. As a result, little pyrophosphate is produced, and calcium accumulates in the blood vessels and other tissues affected by GACI. Alternatively, a lack of functioning MRP6 may impair the transport of a substance that would normally prevent mineralization, leading to the abnormal accumulation of calcium characteristic of GACI. Some people with GACI do not have mutations in the ENPP1 or ABCC6 gene. In these affected individuals, the cause of the disorder is unknown. |
inheritance | Is generalized arterial calcification of infancy inherited ? | 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. |
treatment | What are the treatments for generalized arterial calcification of infancy ? | These resources address the diagnosis or management of GACI: - Gene Review: Gene Review: Generalized Arterial Calcification of Infancy - Genetic Testing Registry: Generalized arterial calcification of infancy 2 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 |
information | What is (are) PPM-X syndrome ? | PPM-X syndrome is a condition characterized by psychotic disorders (most commonly bipolar disorder), a pattern of movement abnormalities known as parkinsonism, and mild to severe intellectual disability. Other symptoms include increased muscle tone and exaggerated reflexes. Affected males may have enlarged testes (macro-orchidism). Not all affected individuals have all these symptoms, but most have intellectual disability. Males with this condition are typically more severely affected than females, who usually have only mild intellectual disability. |
frequency | How many people are affected by PPM-X syndrome ? | The prevalence of PPM-X syndrome is unknown. |
genetic changes | What are the genetic changes related to PPM-X syndrome ? | Mutations in the MECP2 gene cause PPM-X syndrome. 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. The MeCP2 protein likely plays a role in maintaining connections (synapses) between nerve cells. The MeCP2 protein may also control the production of different versions of certain proteins in nerve cells. Although mutations in the MECP2 gene disrupt the normal function of nerve cells, it is unclear how these mutations lead to the signs and symptoms of PPM-X syndrome. Some MECP2 gene mutations that cause PPM-X syndrome disrupt attachment (binding) of the MeCP2 protein to DNA, and other mutations alter the 3-dimensional shape of the protein. These mutations lead to the production of a MeCP2 protein that cannot properly interact with DNA or other proteins and so cannot control the expression of genes. It is unclear how MECP2 gene mutations lead to the signs and symptoms of PPM-X syndrome, but misregulation of genes in the brain likely plays a role. |
inheritance | Is PPM-X syndrome inherited ? | More than 99 percent of PPM-X syndrome cases occur in people with no history of the disorder in their family. Many of these cases result from new mutations in the MECP2 gene. A few families with more than one affected family member have been described. These cases helped researchers determine that PPM-X syndrome has an X-linked pattern of inheritance. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. One copy of the altered gene in each cell is sufficient to cause the condition, although females with one altered copy of the gene are usually less severely affected than males. |
treatment | What are the treatments for PPM-X syndrome ? | These resources address the diagnosis or management of PPM-X syndrome: - Cincinnati Children's Hospital: MECP2-Related Disorders - Gene Review: Gene Review: MECP2-Related Disorders 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 |
information | What is (are) spinocerebellar ataxia type 36 ? | Spinocerebellar ataxia type 36 (SCA36) is a condition characterized by progressive problems with movement that typically begin in mid-adulthood. People with this condition initially experience problems with coordination and balance (ataxia). Affected individuals often have exaggerated reflexes (hyperreflexia) and problems with speech (dysarthria). They also usually develop muscle twitches (fasciculations) of the tongue and over time, the muscles in the tongue waste away (atrophy). These tongue problems can cause difficulties swallowing liquids. As the condition progresses, individuals with SCA36 develop muscle atrophy in the legs, forearms, and hands. Another common feature of SCA36 is the atrophy of specialized nerve cells that control muscle movement (motor neurons), which can contribute to the tongue and limb muscle atrophy in affected individuals. Some people with SCA36 have abnormalities of the eye muscles, which can lead to involuntary eye movements (nystagmus), rapid eye movements (saccades), trouble moving the eyes side-to-side (oculomotor apraxia), and droopy eyelids (ptosis). Sensorineural hearing loss, which is hearing loss caused by changes in the inner ear, may also occur in people with SCA36. Brain imaging of people with SCA36 shows progressive atrophy of various parts of the brain, particularly within the cerebellum, which is the area of the brain involved in coordinating movements. Over time, the loss of cells in the cerebellum causes the movement problems characteristic of SCA36. In older affected individuals, the frontal lobes of the brain may show atrophy resulting in loss of executive function, which is the ability to plan and implement actions and develop problem-solving strategies. Signs and symptoms of SCA36 typically begin in a person's forties or fifties but can appear anytime during adulthood. People with SCA36 have a normal lifespan and are usually mobile for 15 to 20 years after they are diagnosed. |
frequency | How many people are affected by spinocerebellar ataxia type 36 ? | Approximately 100 individuals with SCA36 have been reported in the scientific literature. Almost all of these individuals have been from two regions: western Japan and the Costa de Morte in Galicia, Spain. |
genetic changes | What are the genetic changes related to spinocerebellar ataxia type 36 ? | SCA36 is caused by mutations in the NOP56 gene. The NOP56 gene provides instructions for making a protein called nucleolar protein 56, which is primarily found in the nucleus of nerve cells (neurons), particularly those in the cerebellum. This protein is one part (subunit) of the ribonucleoprotein complex, which is composed of proteins and molecules of RNA, DNA's chemical cousin. The ribonucleoprotein complex is needed to make cellular structures called ribosomes, which process the cell's genetic instructions to create proteins. The NOP56 gene mutations that cause SCA36 involve a string of six DNA building blocks (nucleotides) located in an area of the gene known as intron 1. This string of six nucleotides (known as a hexanucleotide) is represented by the letters GGCCTG and normally appears multiple times in a row. In healthy individuals, GGCCTG is repeated 3 to 14 times within the gene. In people with SCA36, GGCCTG is repeated at least 650 times. It is unclear if 15 to 649 repeats of this hexanucleotide cause any signs or symptoms. To make proteins from the genetic instructions carried in genes, a molecule called messenger RNA (mRNA) is formed. This molecule acts as a genetic blueprint for protein production. However, a large increase in the number of GGCCTG repeats in the NOP56 gene disrupts the normal structure of NOP56 mRNA. Abnormal NOP56 mRNA molecules form clumps called RNA foci within the nucleus of neurons. Other proteins become trapped in the RNA foci, where they cannot function. These proteins may be important for controlling gene activity or protein production. Additionally, researchers believe that the large expansion of the hexanucleotide repeat in the NOP56 gene may reduce the activity of a nearby gene called MIR1292. The MIR1292 gene provides instructions for making a type of RNA that regulates the activity (expression) of genes that produce proteins called glutamate receptors. These proteins are found on the surface of neurons and allow these cells to communicate with one another. A decrease in the production of Mir1292 RNA can lead to an increase in the production of glutamate receptors. The increased receptor activity may overexcite neurons, which disrupts normal communication between cells and can contribute to ataxia. The combination of RNA foci and overly excited neurons likely leads to the death of these cells over time. Because the NOP56 gene is especially active in neurons in the cerebellum, these cells are particularly affected by expansion of the gene, leading to cerebellar atrophy. Deterioration in this part of the brain leads to ataxia and the other signs and symptoms of SCA36. |
inheritance | Is spinocerebellar ataxia type 36 inherited ? | 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 most cases, an affected person has one parent with the condition. In conditions that are caused by repeated segments of DNA, the number of repeats often increases when the altered gene is passed down from one generation to the next. Additionally, a larger number of repeats is usually associated with an earlier onset of signs and symptoms. This phenomenon is called anticipation. Some families affected by SCA36 have demonstrated anticipation while others have not. When anticipation is observed in SCA36, the mutation is most often passed down from the affected father. |
treatment | What are the treatments for spinocerebellar ataxia type 36 ? | These resources address the diagnosis or management of spinocerebellar ataxia type 36: - Ataxia Center at the University of Minnesota: Dominant Spinocerebellar Ataxias - Baylor College of Medicine: Parkinson's Disease Center and Movement Disorders Clinic: Ataxia - Gene Review: Gene Review: Spinocerebellar Ataxia Type 36 - Genetic Testing Registry: Spinocerebellar ataxia 36 - Johns Hopkins Medicine: Ataxia - The Ataxia Center at the University of Chicago: Autosomal Dominant Spinocerebellar Ataxia 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 |
information | What is (are) Niemann-Pick disease ? | Niemann-Pick disease is a condition that affects many body systems. It has a wide range of symptoms that vary in severity. Niemann-Pick disease is divided into four main types: type A, type B, type C1, and type C2. These types are classified on the basis of genetic cause and the signs and symptoms of the condition. Infants with Niemann-Pick disease type A usually develop an enlarged liver and spleen (hepatosplenomegaly) by age 3 months and fail to gain weight and grow at the expected rate (failure to thrive). The affected children develop normally until around age 1 year when they experience a progressive loss of mental abilities and movement (psychomotor regression). Children with Niemann-Pick disease type A also develop widespread lung damage (interstitial lung disease) that can cause recurrent lung infections and eventually lead to respiratory failure. All affected children have an eye abnormality called a cherry-red spot, which can be identified with an eye examination. Children with Niemann-Pick disease type A generally do not survive past early childhood. Niemann-Pick disease type B usually presents in mid-childhood. The signs and symptoms of this type are similar to type A, but not as severe. People with Niemann-Pick disease type B often have hepatosplenomegaly, recurrent lung infections, and a low number of platelets in the blood (thrombocytopenia). They also have short stature and slowed mineralization of bone (delayed bone age). About one-third of affected individuals have the cherry-red spot eye abnormality or neurological impairment. People with Niemann-Pick disease type B usually survive into adulthood. The signs and symptoms of Niemann-Pick disease types C1 and C2 are very similar; these types differ only in their genetic cause. Niemann-Pick disease types C1 and C2 usually become apparent in childhood, although signs and symptoms can develop at any time. People with these types usually develop difficulty coordinating movements (ataxia), an inability to move the eyes vertically (vertical supranuclear gaze palsy), poor muscle tone (dystonia), severe liver disease, and interstitial lung disease. Individuals with Niemann-Pick disease types C1 and C2 have problems with speech and swallowing that worsen over time, eventually interfering with feeding. Affected individuals often experience progressive decline in intellectual function and about one-third have seizures. People with these types may survive into adulthood. |
frequency | How many people are affected by Niemann-Pick disease ? | Niemann-Pick disease types A and B is estimated to affect 1 in 250,000 individuals. Niemann-Pick disease type A occurs more frequently among individuals of Ashkenazi (eastern and central European) Jewish descent than in the general population. The incidence within the Ashkenazi population is approximately 1 in 40,000 individuals. Combined, Niemann-Pick disease types C1 and C2 are estimated to affect 1 in 150,000 individuals; however, type C1 is by far the more common type, accounting for 95 percent of cases. The disease occurs more frequently in people of French-Acadian descent in Nova Scotia. In Nova Scotia, a population of affected French-Acadians were previously designated as having Niemann-Pick disease type D, however, it was shown that these individuals have mutations in the gene associated with Niemann-Pick disease type C1. |
genetic changes | What are the genetic changes related to Niemann-Pick disease ? | Niemann-Pick disease types A and B is caused by mutations in the SMPD1 gene. This gene provides instructions for producing an enzyme called acid sphingomyelinase. This enzyme is found in lysosomes, which are compartments within cells that break down and recycle different types of molecules. Acid sphingomyelinase is responsible for the conversion of a fat (lipid) called sphingomyelin into another type of lipid called ceramide. Mutations in SMPD1 lead to a shortage of acid sphingomyelinase, which results in reduced break down of sphingomyelin, causing this fat to accumulate in cells. This fat buildup causes cells to malfunction and eventually die. Over time, cell loss impairs function of tissues and organs including the brain, lungs, spleen, and liver in people with Niemann-Pick disease types A and B. Mutations in either the NPC1 or NPC2 gene cause Niemann-Pick disease type C. The proteins produced from these genes are involved in the movement of lipids within cells. Mutations in these genes lead to a shortage of functional protein, which prevents movement of cholesterol and other lipids, leading to their accumulation in cells. Because these lipids are not in their proper location in cells, many normal cell functions that require lipids (such as cell membrane formation) are impaired. The accumulation of lipids as well as the cell dysfunction eventually leads to cell death, causing the tissue and organ damage seen in Niemann-Pick disease types C1 and C2. |
inheritance | Is Niemann-Pick disease inherited ? | 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. |
treatment | What are the treatments for Niemann-Pick disease ? | These resources address the diagnosis or management of Niemann-Pick disease: - Baby's First Test - Gene Review: Gene Review: Acid Sphingomyelinase Deficiency - Gene Review: Gene Review: Niemann-Pick Disease Type C - Genetic Testing Registry: Niemann-Pick disease type C1 - Genetic Testing Registry: Niemann-Pick disease type C2 - Genetic Testing Registry: Niemann-Pick disease, type A - Genetic Testing Registry: Niemann-Pick disease, type B - Genetic Testing Registry: Niemann-Pick disease, type C - Genetic Testing Registry: Niemann-Pick disease, type D - Genetic Testing Registry: Niemann-pick disease, intermediate, protracted neurovisceral - Genetic Testing Registry: Sphingomyelin/cholesterol lipidosis - MedlinePlus Encyclopedia: Niemann-Pick Disease 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 |
information | What is (are) RAPADILINO syndrome ? | RAPADILINO syndrome is a rare condition that involves many parts of the body. Bone development is especially affected, causing many of the characteristic features of the condition. Most affected individuals have underdevelopment or absence of the bones in the forearms and the thumbs, which are known as radial ray malformations. The kneecaps (patellae) can also be underdeveloped or absent. Other features include an opening in the roof of the mouth (cleft palate) or a high arched palate; a long, slender nose; and dislocated joints. Many infants with RAPADILINO syndrome have difficulty feeding and experience diarrhea and vomiting. The combination of impaired bone development and feeding problems leads to slow growth and short stature in affected individuals. Some individuals with RAPADILINO syndrome have harmless light brown patches of skin that resemble a skin finding known as caf-au-lait spots. In addition, people with RAPADILINO syndrome have a slightly increased risk of developing a type of bone cancer known as osteosarcoma or a blood-related cancer called lymphoma. In individuals with RAPADILINO syndrome, osteosarcoma most often develops during childhood or adolescence, and lymphoma typically develops in young adulthood. The condition name is an acronym for the characteristic features of the disorder: RA for radial ray malformations, PA for patella and palate abnormalities, DI for diarrhea and dislocated joints, LI for limb abnormalities and little size, and NO for slender nose and normal intelligence. The varied signs and symptoms of RAPADILINO syndrome overlap with features of other disorders, namely Baller-Gerold syndrome and Rothmund-Thomson syndrome. These syndromes are also characterized by radial ray defects, skeletal abnormalities, and slow growth. All of these conditions can be caused by mutations in the same gene. Based on these similarities, researchers are investigating whether Baller-Gerold syndrome, Rothmund-Thomson syndrome, and RAPADILINO syndrome are separate disorders or part of a single syndrome with overlapping signs and symptoms. |
frequency | How many people are affected by RAPADILINO syndrome ? | RAPADILINO syndrome is a rare condition, although its worldwide prevalence is unknown. The condition was first identified in Finland, where it affects an estimated 1 in 75,000 individuals, although it has since been found in other regions. |
genetic changes | What are the genetic changes related to RAPADILINO syndrome ? | Mutations in the RECQL4 gene cause RAPADILINO syndrome. This gene provides instructions for making one member of a protein family called RecQ helicases. Helicases are enzymes that bind to DNA and temporarily unwind the two spiral strands (double helix) of the DNA molecule. This unwinding is necessary for copying (replicating) DNA in preparation for cell division and for repairing damaged DNA. The RECQL4 protein helps stabilize genetic information in the body's cells and plays a role in replicating and repairing DNA. The most common RECQL4 gene mutation involved in RAPADILINO syndrome causes the RECQL4 protein to be pieced together incorrectly. This genetic change results in the production of a protein that is missing a region called exon 7 and is unable to act as a helicase. The loss of helicase function may prevent normal DNA replication and repair, causing widespread damage to a person's genetic information over time. These changes may result in the accumulation of DNA errors and cell death, although it is unclear exactly how RECQL4 gene mutations lead to the specific features of RAPADILINO syndrome. |
inheritance | Is RAPADILINO syndrome inherited ? | 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. |
treatment | What are the treatments for RAPADILINO syndrome ? | These resources address the diagnosis or management of RAPADILINO syndrome: - Genetic Testing Registry: Rapadilino 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 |
information | What is (are) steatocystoma multiplex ? | Steatocystoma multiplex is a skin disorder characterized by the development of multiple noncancerous (benign) cysts known as steatocystomas. These growths begin in the skin's sebaceous glands, which normally produce an oily substance called sebum that lubricates the skin and hair. Steatocystomas are filled with sebum. In affected individuals, steatocystomas typically first appear during adolescence and are found most often on the torso, neck, upper arms, and upper legs. In most people with steatocystoma multiplex, these cysts are the only sign of the condition. However, some affected individuals also have mild abnormalities involving the teeth or the fingernails and toenails. |
frequency | How many people are affected by steatocystoma multiplex ? | Although the prevalence of steatocystoma multiplex is unknown, it appears to be rare. |
genetic changes | What are the genetic changes related to steatocystoma multiplex ? | Steatocystoma multiplex can be caused by mutations in the KRT17 gene. This gene provides instructions for making a protein called keratin 17, which is produced in the nails, the hair follicles, and the skin on the palms of the hands and soles of the feet. It is also found in the skin's sebaceous glands. Keratin 17 partners with a similar protein called keratin 6b to form networks that provide strength and resilience to the skin, nails, and other tissues. The KRT17 gene mutations that cause steatocystoma multiplex alter the structure of keratin 17, preventing it from forming strong, stable networks within cells. The defective keratin network disrupts the growth and function of cells in the skin and nails, including cells that make up the sebaceous glands. These abnormalities lead to the growth of sebum-containing cysts in people with steatocystoma multiplex. However, it is unclear why steatocystomas are typically the only feature of this disorder. Many researchers believe that steatocystoma multiplex is a variant form of a disorder called pachyonychia congenita, which can also result from mutations in the KRT17 gene. Like steatocystoma multiplex, pachyonychia congenita involves the growth of steatocystomas. Pachyonychia congenita is also associated with more severe skin and nail abnormalities not usually found in people with steatocystoma multiplex. In some cases, people with steatocystoma multiplex do not have an identified mutation in the KRT17 gene. The cause of the condition in these individuals is unknown. |
inheritance | Is steatocystoma multiplex inherited ? | When steatocystoma multiplex is caused by mutations in the KRT17 gene, it is inherited in an autosomal dominant pattern. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the condition from an affected parent. In people with steatocystoma multiplex who do not have identified KRT17 gene mutations, there is usually no family history of the disorder. |
treatment | What are the treatments for steatocystoma multiplex ? | These resources address the diagnosis or management of steatocystoma multiplex: - Genetic Testing Registry: Steatocystoma multiplex 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 |
information | What is (are) alpha-mannosidosis ? | Alpha-mannosidosis is a rare inherited disorder that causes problems in many organs and tissues of the body. Affected individuals may have intellectual disability, distinctive facial features, and skeletal abnormalities. Characteristic facial features can include a large head, prominent forehead, low hairline, rounded eyebrows, large ears, flattened bridge of the nose, protruding jaw, widely spaced teeth, overgrown gums, and large tongue. The skeletal abnormalities that can occur in this disorder include reduced bone density (osteopenia), thickening of the bones at the top of the skull (calvaria), deformations of the bones in the spine (vertebrae), bowed legs or knock knees, and deterioration of the bones and joints. Affected individuals may also experience difficulty in coordinating movements (ataxia); muscle weakness (myopathy); delay in developing motor skills such as sitting and walking; speech impairments; increased risk of infections; enlargement of the liver and spleen (hepatosplenomegaly); a buildup of fluid in the brain (hydrocephalus); hearing loss; and a clouding of the lens of the eye (cataract). Some people with alpha-mannosidosis experience psychiatric symptoms such as depression, anxiety, or hallucinations; episodes of psychiatric disturbance may be triggered by stressors such as having undergone surgery, emotional upset, or changes in routine. The signs and symptoms of alpha-mannosidosis can range from mild to severe. The disorder may appear in infancy with rapid progression and severe neurological deterioration. Individuals with this early-onset form of alpha-mannosidosis often do not survive past childhood. In the most severe cases, an affected fetus may die before birth. Other individuals with alpha-mannosidosis experience milder signs and symptoms that appear later and progress more slowly. People with later-onset alpha-mannosidosis may survive into their fifties. The mildest cases may be detected only through laboratory testing and result in few if any symptoms. |
frequency | How many people are affected by alpha-mannosidosis ? | Alpha-mannosidosis is estimated to occur in approximately 1 in 500,000 people worldwide. |
genetic changes | What are the genetic changes related to alpha-mannosidosis ? | Mutations in the MAN2B1 gene cause alpha-mannosidosis. This gene provides instructions for making the enzyme alpha-mannosidase. This enzyme works in the lysosomes, which are compartments that digest and recycle materials in the cell. Within lysosomes, the enzyme helps break down complexes of sugar molecules (oligosaccharides) attached to certain proteins (glycoproteins). In particular, alpha-mannosidase helps break down oligosaccharides containing a sugar molecule called mannose. Mutations in the MAN2B1 gene interfere with the ability of the alpha-mannosidase enzyme to perform its role in breaking down mannose-containing oligosaccharides. These oligosaccharides accumulate in the lysosomes and cause cells to malfunction and eventually die. Tissues and organs are damaged by the abnormal accumulation of oligosaccharides and the resulting cell death, leading to the characteristic features of alpha-mannosidosis. |
inheritance | Is alpha-mannosidosis inherited ? | 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. |
treatment | What are the treatments for alpha-mannosidosis ? | These resources address the diagnosis or management of alpha-mannosidosis: - Gene Review: Gene Review: Alpha-Mannosidosis - Genetic Testing Registry: Deficiency of alpha-mannosidase 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 |
information | What is (are) Freeman-Sheldon syndrome ? | Freeman-Sheldon syndrome is a condition that primarily affects the face, hands, and feet. People with this disorder have a distinctive facial appearance including a small mouth (microstomia) with pursed lips, giving the appearance of a "whistling face." For this reason, the condition is sometimes called "whistling face syndrome." People with Freeman-Sheldon syndrome may also have a prominent forehead and brow ridges, a sunken appearance of the middle of the face (midface hypoplasia), a short nose, a long area between the nose and mouth (philtrum), deep folds in the skin between the nose and lips (nasolabial folds), full cheeks, and a chin dimple shaped like an "H" or "V". Affected individuals may have a number of abnormalities that affect the eyes. These may include widely spaced eyes (hypertelorism), deep-set eyes, outside corners of the eyes that point downward (down-slanting palpebral fissures), a narrowing of the eye opening (blepharophimosis), droopy eyelids (ptosis), and eyes that do not look in the same direction (strabismus). Other facial features that may occur in Freeman-Sheldon syndrome include an unusually small tongue (microglossia) and jaw (micrognathia) and a high arch in the roof of the mouth (high-arched palate). People with this disorder may have difficulty swallowing (dysphagia), a failure to gain weight and grow at the expected rate (failure to thrive), and respiratory complications that may be life-threatening. Speech problems are also common in this disorder. Some affected individuals have hearing loss. Freeman-Sheldon syndrome is also characterized by joint deformities (contractures) that restrict movement. People with this disorder typically have multiple contractures in the hands and feet at birth (distal arthrogryposis). These contractures lead to permanently bent fingers and toes (camptodactyly), a hand deformity in which all of the fingers are angled outward toward the fifth finger (ulnar deviation, also called "windmill vane hand"), and inward- and downward-turning feet (clubfoot). Affected individuals may also have a spine that curves to the side (scoliosis). People with Freeman-Sheldon syndrome also have an increased risk of developing a severe reaction to certain drugs used during surgery and other invasive procedures. This reaction is called malignant hyperthermia. Malignant hyperthermia occurs in response to some anesthetic gases, which are used to block the sensation of pain. A particular type of muscle relaxant may also trigger the reaction. If given these drugs, people at risk for malignant hyperthermia may experience muscle rigidity, breakdown of muscle fibers (rhabdomyolysis), a high fever, increased acid levels in the blood and other tissues (acidosis), and a rapid heart rate. The complications of malignant hyperthermia can be life-threatening unless they are treated promptly. Intelligence is unaffected in most people with Freeman-Sheldon syndrome, but approximately one-third have some degree of intellectual disability. |
frequency | How many people are affected by Freeman-Sheldon syndrome ? | Freeman-Sheldon syndrome is a rare disorder; its exact prevalence is unknown. |
genetic changes | What are the genetic changes related to Freeman-Sheldon syndrome ? | Freeman-Sheldon syndrome may be caused by mutations in the MYH3 gene. The MYH3 gene provides instructions for making a protein called embryonic skeletal muscle myosin heavy chain 3. This protein belongs to a group of proteins called myosins, which are involved in cell movement and transport of materials within and between cells. Myosin and another protein called actin are the primary components of muscle fibers and are important for the tensing of muscles (muscle contraction). Embryonic skeletal muscle myosin heavy chain 3 forms part of a myosin protein complex that is active before birth and is important for normal development of the muscles. MYH3 gene mutations that cause Freeman-Sheldon syndrome likely disrupt the function of the embryonic skeletal muscle myosin heavy chain 3 protein, reducing the ability of fetal muscle cells to contract. This impairment of muscle contraction may interfere with muscle development in the fetus, resulting in the contractures and other muscle and skeletal abnormalities associated with Freeman-Sheldon syndrome. It is unclear how MYH3 gene mutations may cause other features of this disorder. Some people with Freeman-Sheldon syndrome do not have mutations in the MYH3 gene. In these individuals, the cause of the disorder is unknown. |
inheritance | Is Freeman-Sheldon syndrome inherited ? | Freeman-Sheldon syndrome can have different inheritance patterns. In some cases, the 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. The condition can also have an autosomal recessive inheritance 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. In some cases, the inheritance pattern is unknown. |
treatment | What are the treatments for Freeman-Sheldon syndrome ? | These resources address the diagnosis or management of Freeman-Sheldon syndrome: - Genetic Testing Registry: Freeman-Sheldon 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 |
information | What is (are) severe congenital neutropenia ? | Severe congenital neutropenia is a condition that causes affected individuals to be prone to recurrent infections. People with this condition have a shortage (deficiency) of neutrophils, a type of white blood cell that plays a role in inflammation and in fighting infection. The deficiency of neutrophils, called neutropenia, is apparent at birth or soon afterward. It leads to recurrent infections beginning in infancy, including infections of the sinuses, lungs, and liver. Affected individuals can also develop fevers and inflammation of the gums (gingivitis) and skin. Approximately 40 percent of affected people have decreased bone density (osteopenia) and may develop osteoporosis, a condition that makes bones progressively more brittle and prone to fracture. In people with severe congenital neutropenia, these bone disorders can begin at any time from infancy through adulthood. Approximately 20 percent of people with severe congenital neutropenia develop cancer of the blood-forming tissue (leukemia) or a disease of the blood and bone marrow (myelodysplastic syndrome) during adolescence. Some people with severe congenital neutropenia have additional health problems such as seizures, developmental delay, or heart and genital abnormalities. |
frequency | How many people are affected by severe congenital neutropenia ? | The incidence of severe congenital neutropenia is estimated to be 1 in 200,000 individuals. |
genetic changes | What are the genetic changes related to severe congenital neutropenia ? | Severe congenital neutropenia can result from mutations in at least five different genes. These genes play a role in the maturation and function of neutrophils, which are cells produced by the bone marrow. Neutrophils secrete immune molecules and ingest and break down foreign invaders. Gene mutations that cause severe congenital neutropenia lead to the production of neutrophils that die off quickly or do not function properly. Some gene mutations result in unstable proteins that build up in neutrophils, leading to cell death. Other gene mutations result in proteins that impair the maturation or function of neutrophils, preventing these cells from responding appropriately to immune signals. About half of all cases of severe congenital neutropenia are caused by mutations in the ELANE gene. Another 15 percent are caused by mutations in the HAX1 gene. The other genes each account for only a small percentage of all cases of this condition. In about one-third of people with severe congenital neutropenia, the cause of the disorder is unknown. |
inheritance | Is severe congenital neutropenia inherited ? | Most cases of severe congenital neutropenia are classified as sporadic and occur in people with no apparent history of the disorder in their family. Some of these cases are associated with changes in specific genes; however in some cases the cause of the disorder is unknown. Many cases of severe congenital neutropenia are inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Less often, 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. In rare cases, severe congenital neutropenia is inherited in an X-linked recessive pattern. In these cases, the gene that causes the 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. |
treatment | What are the treatments for severe congenital neutropenia ? | These resources address the diagnosis or management of severe congenital neutropenia: - Cincinnati Children's Hospital: The Severe Congenital Neutropenia International Registry - Gene Review: Gene Review: ELANE-Related Neutropenia - Gene Review: Gene Review: G6PC3 Deficiency - Genetic Testing Registry: Severe congenital neutropenia - Genetic Testing Registry: Severe congenital neutropenia 2, autosomal dominant - Genetic Testing Registry: Severe congenital neutropenia 4, autosomal recessive - Genetic Testing Registry: Severe congenital neutropenia X-linked - Genetic Testing Registry: Severe congenital neutropenia autosomal dominant - MedlinePlus Encyclopedia: Neutropenia--infants 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 |
information | What is (are) Vohwinkel syndrome ? | Vohwinkel syndrome is a disorder with classic and variant forms, both of which affect the skin. In the classic form of Vohwinkel syndrome, affected individuals have thick, honeycomb-like calluses on the palms of the hands and soles of the feet (palmoplantar keratoses) beginning in infancy or early childhood. Affected children also typically have distinctive starfish-shaped patches of thickened skin on the tops of the fingers and toes or on the knees. Within a few years they develop tight bands of abnormal fibrous tissue around their fingers and toes (pseudoainhum); the bands may cut off the circulation to the digits and result in spontaneous amputation. People with the classic form of the disorder also have hearing loss. The variant form of Vohwinkel syndrome does not involve hearing loss, and the skin features also include widespread dry, scaly skin (ichthyosis), especially on the limbs. The ichthyosis is usually mild, and there may also be mild reddening of the skin (erythroderma). Some affected infants are born with a tight, clear sheath covering their skin called a collodion membrane. This membrane is usually shed during the first few weeks of life. |
frequency | How many people are affected by Vohwinkel syndrome ? | Vohwinkel syndrome is a rare disorder; about 50 cases have been reported in the medical literature. |
genetic changes | What are the genetic changes related to Vohwinkel syndrome ? | The classic form of Vohwinkel syndrome 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, maturation, and stability of the outermost layer of skin (the epidermis). The GJB2 gene mutations that cause Vohwinkel syndrome change single protein building blocks (amino acids) in connexin 26. The altered protein probably disrupts the function of normal connexin 26 in cells, and may interfere with the function of other connexin proteins. This disruption could affect skin growth and also impair hearing by disturbing the conversion of sound waves to nerve impulses. The variant form of Vohwinkel syndrome, sometimes called loricrin keratoderma, is caused by mutations in the LOR gene. This gene provides instructions for making a protein called loricrin, which is involved in the formation and maintenance of the epidermis, particularly its tough outer surface (the stratum corneum). The stratum corneum, which is formed in a process known as cornification, provides a sturdy barrier between the body and its environment. Each cell of the stratum corneum, called a corneocyte, is surrounded by a protein shell called a cornified envelope. Loricrin is a major component of the cornified envelope. Links between loricrin and other components of the envelopes hold the corneocytes together and help give the stratum corneum its strength. Mutations in the LOR gene change the structure of the loricrin protein; the altered protein is trapped inside the cell and cannot reach the cornified envelope. While other proteins can partially compensate for the missing loricrin, the envelope of some corneocytes is thinner than normal in affected individuals, resulting in ichthyosis and the other skin abnormalities associated with the variant form of Vohwinkel syndrome. |
inheritance | Is Vohwinkel syndrome inherited ? | 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 most 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. |
treatment | What are the treatments for Vohwinkel syndrome ? | These resources address the diagnosis or management of Vohwinkel syndrome: - Genetic Testing Registry: Mutilating keratoderma - Genetic Testing Registry: Vohwinkel syndrome, variant form 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 |
information | What is (are) thanatophoric dysplasia ? | Thanatophoric dysplasia is a severe skeletal disorder characterized by extremely short limbs and folds of extra (redundant) skin on the arms and legs. Other features of this condition include a narrow chest, short ribs, underdeveloped lungs, and an enlarged head with a large forehead and prominent, wide-spaced eyes. Researchers have described two major forms of thanatophoric dysplasia, type I and type II. Type I thanatophoric dysplasia is distinguished by the presence of curved thigh bones and flattened bones of the spine (platyspondyly). Type II thanatophoric dysplasia is characterized by straight thigh bones and a moderate to severe skull abnormality called a cloverleaf skull. The term thanatophoric is Greek for "death bearing." Infants with thanatophoric dysplasia are usually stillborn or die shortly after birth from respiratory failure; however, a few affected individuals have survived into childhood with extensive medical help. |
frequency | How many people are affected by thanatophoric dysplasia ? | This condition occurs in 1 in 20,000 to 50,000 newborns. Type I thanatophoric dysplasia is more common than type II. |
genetic changes | What are the genetic changes related to thanatophoric dysplasia ? | Mutations in the FGFR3 gene cause thanatophoric dysplasia. Both types of this condition result from mutations in the FGFR3 gene. This gene provides instructions for making a protein that is involved in the development and maintenance of bone and brain tissue. Mutations in this gene cause the FGFR3 protein to be overly active, which leads to the severe disturbances in bone growth that are characteristic of thanatophoric dysplasia. It is not known how FGFR3 mutations cause the brain and skin abnormalities associated with this disorder. |
inheritance | Is thanatophoric dysplasia inherited ? | Thanatophoric dysplasia is considered an autosomal dominant disorder because one mutated copy of the FGFR3 gene in each cell is sufficient to cause the condition. Virtually all cases of thanatophoric dysplasia are caused by new mutations in the FGFR3 gene and occur in people with no history of the disorder in their family. No affected individuals are known to have had children; therefore, the disorder has not been passed to the next generation. |
treatment | What are the treatments for thanatophoric dysplasia ? | These resources address the diagnosis or management of thanatophoric dysplasia: - Gene Review: Gene Review: Thanatophoric Dysplasia - Genetic Testing Registry: Thanatophoric dysplasia type 1 - Genetic Testing Registry: Thanatophoric dysplasia, type 2 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 |
information | What is (are) GRACILE syndrome ? | GRACILE syndrome is a severe disorder that begins before birth. GRACILE stands for the condition's characteristic features: growth retardation, aminoaciduria, cholestasis, iron overload, lactic acidosis, and early death. In GRACILE syndrome, growth before birth is slow (intrauterine growth retardation). Affected newborns are smaller than average and have an inability to grow and gain weight at the expected rate (failure to thrive). A characteristic of GRACILE syndrome is excess iron in the liver, which likely begins before birth. Iron levels may begin to improve after birth, although they typically remain elevated. Within the first day of life, infants with GRACILE syndrome have a buildup of a chemical called lactic acid in the body (lactic acidosis). They also have kidney problems that lead to an excess of molecules called amino acids in the urine (aminoaciduria). Babies with GRACILE syndrome have cholestasis, which is a reduced ability to produce and release a digestive fluid called bile. Cholestasis leads to irreversible liver disease (cirrhosis) in the first few months of life. Because of the severe health problems caused by GRACILE syndrome, infants with this condition do not survive for more than a few months, and about half die within a few days of birth. |
frequency | How many people are affected by GRACILE syndrome ? | GRACILE syndrome is found almost exclusively in Finland, where it is estimated to affect 1 in 47,000 infants. At least 32 affected infants have been described in the medical literature. |
genetic changes | What are the genetic changes related to GRACILE syndrome ? | GRACILE syndrome is caused by a mutation in the BCS1L gene. The protein produced from this gene is found in cell structures called mitochondria, which convert the energy from food into a form that cells can use. In mitochondria, the BCS1L protein plays a role in oxidative phosphorylation, which is a multistep process through which cells derive much of their energy. The BCS1L protein is critical for the formation of a group of proteins known as complex III, which is one of several protein complexes involved in oxidative phosphorylation. The genetic change involved in GRACILE syndrome alters the BCS1L protein, and the abnormal protein is broken down more quickly than the normal protein. What little protein remains is able to help form some complete complex III, although the amount is severely reduced, particularly in the liver and kidneys. As a result, complex III activity and oxidative phosphorylation are decreased in these organs in people with GRACILE syndrome. Without energy, these organs become damaged, leading to many of the features of GRACILE syndrome. It is not clear why a change in the BCS1L gene leads to iron accumulation in people with this condition. |
inheritance | Is GRACILE syndrome inherited ? | 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. |
treatment | What are the treatments for GRACILE syndrome ? | These resources address the diagnosis or management of GRACILE syndrome: - Genetic Testing Registry: GRACILE syndrome - MedlinePlus Encyclopedia: Aminoaciduria - MedlinePlus Encyclopedia: Cholestasis 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 |
information | What is (are) coloboma ? | Coloboma is an eye abnormality that occurs before birth. Colobomas are missing pieces of tissue in structures that form the eye. They may appear as notches or gaps in one of several parts of the eye, including the colored part of the eye called the iris; the retina, which is the specialized light-sensitive tissue that lines the back of the eye; the blood vessel layer under the retina called the choroid; or the optic nerves, which carry information from the eyes to the brain. Colobomas may be present in one or both eyes and, depending on their size and location, can affect a person's vision. Colobomas affecting the iris, which result in a "keyhole" appearance of the pupil, generally do not lead to vision loss. Colobomas involving the retina result in vision loss in specific parts of the visual field, generally the upper part. Large retinal colobomas or those affecting the optic nerve can cause low vision, which means vision loss that cannot be completely corrected with glasses or contact lenses. Some people with coloboma also have a condition called microphthalmia. In this condition, one or both eyeballs are abnormally small. In some affected individuals, the eyeball may appear to be completely missing; however, even in these cases some remaining eye tissue is generally present. Such severe microphthalmia should be distinguished from another condition called anophthalmia, in which no eyeball forms at all. However, the terms anophthalmia and severe microphthalmia are often used interchangeably. Microphthalmia may or may not result in significant vision loss. People with coloboma may also have other eye abnormalities, including clouding of the lens of the eye (cataract), increased pressure inside the eye (glaucoma) that can damage the optic nerve, vision problems such as nearsightedness (myopia), involuntary back-and-forth eye movements (nystagmus), or separation of the retina from the back of the eye (retinal detachment). Some individuals have coloboma as part of a syndrome that affects other organs and tissues in the body. These forms of the condition are described as syndromic. When coloboma occurs by itself, it is described as nonsyndromic or isolated. Colobomas involving the eyeball should be distinguished from gaps that occur in the eyelids. While these eyelid gaps are also called colobomas, they arise from abnormalities in different structures during early development. |
frequency | How many people are affected by coloboma ? | Coloboma occurs in approximately 1 in 10,000 people. Because coloboma does not always affect vision or the outward appearance of the eye, some people with this condition are likely undiagnosed. |
genetic changes | What are the genetic changes related to coloboma ? | Coloboma arises from abnormal development of the eye. During the second month of development before birth, a seam called the optic fissure (also known as the choroidal fissure or embryonic fissure) closes to form the structures of the eye. When the optic fissure does not close completely, the result is a coloboma. The location of the coloboma depends on the part of the optic fissure that failed to close. Coloboma may be caused by changes in many genes involved in the early development of the eye, most of which have not been identified. The condition may also result from a chromosomal abnormality affecting one or more genes. Most genetic changes associated with coloboma have been identified only in very small numbers of affected individuals. The risk of coloboma may also be increased by environmental factors that affect early development, such as exposure to alcohol during pregnancy. In these cases, affected individuals usually have other health problems in addition to coloboma. |
inheritance | Is coloboma inherited ? | Most often, isolated coloboma is not inherited, and there is only one affected individual in a family. However, the affected individual is still at risk of passing the coloboma on to his or her own children. In cases when it is passed down in families, coloboma can have different inheritance patterns. Isolated coloboma is sometimes inherited in an autosomal dominant pattern, which means one copy of an altered gene in each cell is sufficient to cause the disorder. Isolated coloboma can also be inherited in an autosomal recessive pattern, which means both copies of a gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of a mutated gene, but they typically do not show signs and symptoms of the condition. Less commonly, isolated coloboma may have X-linked dominant or X-linked recessive patterns of inheritance. X-linked means that a gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. X-linked dominant means that in females (who have two X chromosomes), a mutation in one of the two copies of a gene in each cell is sufficient to cause the disorder. In males (who have only one X chromosome), a mutation in the only copy of a gene in each cell causes the disorder. In most cases, males experience more severe symptoms of the disorder than females. X-linked recessive means that in females, a mutation would have to occur in both copies of a gene to cause the disorder. In males, one altered copy of a gene in each cell is sufficient to cause the condition. Because it is unlikely that females will have two altered copies of a particular gene, males are affected by X-linked recessive disorders much more frequently than females. When coloboma occurs as a feature of a genetic syndrome or chromosomal abnormality, it may cluster in families according to the inheritance pattern for that condition, which may be autosomal dominant, autosomal recessive, or X-linked. |
treatment | What are the treatments for coloboma ? | These resources address the diagnosis or management of coloboma: - Genetic Testing Registry: Congenital ocular coloboma - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 1 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 2 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 3 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 4 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 5 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 6 - National Eye Institute: Facts About Uveal Coloboma 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 |
information | What is (are) Brody myopathy ? | Brody myopathy is a condition that affects the skeletal muscles, which are the muscles used for movement. Affected individuals experience muscle cramping and stiffening after exercise or other strenuous activity, especially in cold temperatures. These symptoms typically begin in childhood. They are usually painless, but in some cases can cause mild discomfort. The muscles usually relax after a few minutes of rest. Most commonly affected are the muscles of the arms, legs, and face (particularly the eyelids). In some people with Brody myopathy, exercise leads to the breakdown of muscle tissue (rhabdomyolysis). The destruction of muscle tissue releases a protein called myoglobin, which is processed by the kidneys and released in the urine (myoglobinuria). Myoglobin causes the urine to be red or brown. |
frequency | How many people are affected by Brody myopathy ? | Brody myopathy is a rare condition, although its exact prevalence is unknown. |
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