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What are the genetic changes related to episodic ataxia ?
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Episodic ataxia can be caused by mutations in several genes that play important roles in the nervous system. Three of these genes, KCNA1, CACNA1A, and CACNB4, provide instructions for making proteins that are involved in the transport of charged atoms (ions) across cell membranes. The movement of these ions is critical for normal signaling between nerve cells (neurons) in the brain and other parts of the nervous system. Mutations in the KCNA1, CACNA1A, and CACNB4 genes are responsible for episodic ataxia types 1, 2, and 5, respectively. Mutations in the SLC1A3 gene have been found to cause episodic ataxia type 6. This gene provides instructions for making a protein that transports a brain chemical (neurotransmitter) called glutamate. Neurotransmitters, including glutamate, allow neurons to communicate by relaying chemical signals from one neuron to another. Researchers believe that mutations in the KCNA1, CACNA1A, CACNB4, and SLC1A3 genes alter the transport of ions and glutamate in the brain, which causes certain neurons to become overexcited and disrupts normal communication between these cells. Although changes in chemical signaling in the brain underlie the recurrent attacks seen in people with episodic ataxia, it is unclear how mutations in these genes cause the specific features of the disorder. The genetic causes of episodic ataxia types 3, 4, and 7 have not been identified. Researchers are looking for additional genes that can cause episodic ataxia.
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Is episodic ataxia inherited ?
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This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family.
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What are the treatments for episodic ataxia ?
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These resources address the diagnosis or management of episodic ataxia: - Consortium for Clinical Investigations of Neurological Channelopathies (CINCH) - Gene Review: Gene Review: Episodic Ataxia Type 1 - Gene Review: Gene Review: Episodic Ataxia Type 2 - Genetic Testing Registry: Episodic ataxia type 1 - Genetic Testing Registry: Episodic ataxia type 2 - Genetic Testing Registry: Episodic ataxia, type 3 - Genetic Testing Registry: Episodic ataxia, type 4 - Genetic Testing Registry: Episodic ataxia, type 7 - MedlinePlus Encyclopedia: Movement - uncoordinated - MedlinePlus Encyclopedia: Vertigo-associated 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
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What is (are) Crouzon syndrome ?
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Crouzon syndrome is a genetic disorder characterized by the premature fusion of certain skull bones (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face. Many features of Crouzon syndrome result from the premature fusion of the skull bones. Abnormal growth of these bones leads to wide-set, bulging eyes and vision problems caused by shallow eye sockets; eyes that do not point in the same direction (strabismus); a beaked nose; and an underdeveloped upper jaw. In addition, people with Crouzon syndrome may have dental problems and hearing loss, which is sometimes accompanied by narrow ear canals. A few people with Crouzon syndrome have an opening in the lip and the roof of the mouth (cleft lip and palate). The severity of these signs and symptoms varies among affected people. People with Crouzon syndrome are usually of normal intelligence.
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How many people are affected by Crouzon syndrome ?
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Crouzon syndrome is seen in about 16 per million newborns. It is the most common craniosynostosis syndrome.
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What are the genetic changes related to Crouzon syndrome ?
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Mutations in the FGFR2 gene cause Crouzon syndrome. This gene provides instructions for making a protein called fibroblast growth factor receptor 2. Among its multiple functions, this protein signals immature cells to become bone cells during embryonic development. Mutations in the FGFR2 gene probably overstimulate signaling by the FGFR2 protein, which causes the bones of the skull to fuse prematurely.
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Is Crouzon syndrome inherited ?
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This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
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What are the treatments for Crouzon syndrome ?
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These resources address the diagnosis or management of Crouzon syndrome: - Gene Review: Gene Review: FGFR-Related Craniosynostosis Syndromes - Genetic Testing Registry: Crouzon syndrome - MedlinePlus Encyclopedia: Craniosynostosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) leukocyte adhesion deficiency type 1 ?
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Leukocyte adhesion deficiency type 1 is a disorder that causes the immune system to malfunction, resulting in a form of immunodeficiency. Immunodeficiencies are conditions in which the immune system is not able to protect the body effectively from foreign invaders such as viruses, bacteria, and fungi. Starting from birth, people with leukocyte adhesion deficiency type 1 develop serious bacterial and fungal infections. One of the first signs of leukocyte adhesion deficiency type 1 is a delay in the detachment of the umbilical cord stump after birth. In newborns, the stump normally falls off within the first two weeks of life; but, in infants with leukocyte adhesion deficiency type 1, this separation usually occurs at three weeks or later. In addition, affected infants often have inflammation of the umbilical cord stump (omphalitis) due to a bacterial infection. In leukocyte adhesion deficiency type 1, bacterial and fungal infections most commonly occur on the skin and mucous membranes such as the moist lining of the nose and mouth. In childhood, people with this condition develop severe inflammation of the gums (gingivitis) and other tissue around the teeth (periodontitis), which often results in the loss of both primary and permanent teeth. These infections often spread to cover a large area. A hallmark of leukocyte adhesion deficiency type 1 is the lack of pus formation at the sites of infection. In people with this condition, wounds are slow to heal, which can lead to additional infection. Life expectancy in individuals with leukocyte adhesion deficiency type 1 is often severely shortened. Due to repeat infections, affected individuals may not survive past infancy.
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How many people are affected by leukocyte adhesion deficiency type 1 ?
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Leukocyte adhesion deficiency type 1 is estimated to occur in 1 per million people worldwide. At least 300 cases of this condition have been reported in the scientific literature.
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What are the genetic changes related to leukocyte adhesion deficiency type 1 ?
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Mutations in the ITGB2 gene cause leukocyte adhesion deficiency type 1. This gene provides instructions for making one part (the 2 subunit) of at least four different proteins known as 2 integrins. Integrins that contain the 2 subunit are found embedded in the membrane that surrounds white blood cells (leukocytes). These integrins help leukocytes gather at sites of infection or injury, where they contribute to the immune response. 2 integrins recognize signs of inflammation and attach (bind) to proteins called ligands on the lining of blood vessels. This binding leads to linkage (adhesion) of the leukocyte to the blood vessel wall. Signaling through the 2 integrins triggers the transport of the attached leukocyte across the blood vessel wall to the site of infection or injury. ITGB2 gene mutations that cause leukocyte adhesion deficiency type 1 lead to the production of a 2 subunit that cannot bind with other subunits to form 2 integrins. Leukocytes that lack these integrins cannot attach to the blood vessel wall or cross the vessel wall to contribute to the immune response. As a result, there is a decreased response to injury and foreign invaders, such as bacteria and fungi, resulting in frequent infections, delayed wound healing, and other signs and symptoms of this condition.
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Is leukocyte adhesion deficiency type 1 inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for leukocyte adhesion deficiency type 1 ?
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These resources address the diagnosis or management of leukocyte adhesion deficiency type 1: - Genetic Testing Registry: Leukocyte adhesion deficiency type 1 - MedlinePlus Encyclopedia: Gingivitis - MedlinePlus Encyclopedia: Immunodeficiency Disorders - Primary Immune Deficiency Treatment Consortium These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) Weaver syndrome ?
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Weaver syndrome is a condition that involves tall stature with or without a large head size (macrocephaly), a variable degree of intellectual disability (usually mild), and characteristic facial features. These features can include a broad forehead; widely spaced eyes (hypertelorism); large, low-set ears; a dimpled chin, and a small lower jaw (micrognathia). People with Weaver syndrome can also have joint deformities called contractures that restrict the movement of affected joints. The contractures may particularly affect the fingers and toes, resulting in permanently bent digits (camptodactyly). Other features of this disorder can include abnormal curvature of the spine (kyphoscoliosis); muscle tone that is either reduced (hypotonia) or increased (hypertonia); loose, saggy skin; and a soft-outpouching around the belly-button (umbilical hernia). Some affected individuals have abnormalities in the folds (gyri) of the brain, which can be seen by medical imaging; the relationship between these brain abnormalities and the intellectual disability associated with Weaver syndrome is unclear. Researchers suggest that people with Weaver syndrome may have an increased risk of developing cancer, in particular a slightly increased risk of developing a tumor called neuroblastoma in early childhood, but the small number of affected individuals makes it difficult to determine the exact risk.
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How many people are affected by Weaver syndrome ?
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The prevalence of Weaver syndrome is unknown. About 50 affected individuals have been described in the medical literature.
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What are the genetic changes related to Weaver syndrome ?
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Weaver syndrome is usually caused by mutations in the EZH2 gene. The EZH2 gene provides instructions for making a type of enzyme called a histone methyltransferase. Histone methyltransferases modify proteins called histones, which are structural proteins that attach (bind) to DNA and give chromosomes their shape. By adding a molecule called a methyl group to histones (methylation), histone methyltransferases can turn off the activity of certain genes, which is an essential process in normal development. It is unclear how mutations in the EZH2 gene result in the abnormalities characteristic of Weaver syndrome.
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Is Weaver syndrome inherited ?
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This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most cases result from new mutations in the gene and occur in people with no history of the disorder in their family. In a small number of cases, an affected person inherits the mutation from one affected parent.
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What are the treatments for Weaver syndrome ?
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These resources address the diagnosis or management of Weaver syndrome: - Genetic Testing Registry: Weaver syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) molybdenum cofactor deficiency ?
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Molybdenum cofactor deficiency is a rare condition characterized by brain dysfunction (encephalopathy) that worsens over time. Babies with this condition appear normal at birth, but within a week they have difficulty feeding and develop seizures that do not improve with treatment (intractable seizures). Brain abnormalities, including deterioration (atrophy) of brain tissue, lead to severe developmental delay; affected individuals usually do not learn to sit unassisted or to speak. A small percentage of affected individuals have an exaggerated startle reaction (hyperekplexia) to unexpected stimuli such as loud noises. Other features of molybdenum cofactor deficiency can include a small head size (microcephaly) and facial features that are described as "coarse." Tests reveal that affected individuals have high levels of chemicals called sulfite, S-sulfocysteine, xanthine, and hypoxanthine in the urine and low levels of a chemical called uric acid in the blood. Because of the serious health problems caused by molybdenum cofactor deficiency, affected individuals usually do not survive past early childhood.
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How many people are affected by molybdenum cofactor deficiency ?
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Molybdenum cofactor deficiency is a rare condition that is estimated to occur in 1 in 100,000 to 200,000 newborns worldwide. More than 100 cases have been reported in the medical literature, although it is thought that the condition is underdiagnosed, so the number of affected individuals may be higher.
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What are the genetic changes related to molybdenum cofactor deficiency ?
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Molybdenum cofactor deficiency is caused by mutations in the MOCS1, MOCS2, or GPHN gene. There are three forms of the disorder, named types A, B, and C (or complementation groups A, B, and C). The forms have the same signs and symptoms but are distinguished by their genetic cause: MOCS1 gene mutations cause type A, MOCS2 gene mutations cause type B, and GPHN gene mutations cause type C. The proteins produced from each of these genes are involved in the formation (biosynthesis) of a molecule called molybdenum cofactor. Molybdenum cofactor, which contains the element molybdenum, is essential to the function of several enzymes. These enzymes help break down (metabolize) different substances in the body, some of which are toxic if not metabolized. Mutations in the MOCS1, MOCS2, or GPHN gene reduce or eliminate the function of the associated protein, which impairs molybdenum cofactor biosynthesis. Without the cofactor, the metabolic enzymes that rely on it cannot function. The resulting loss of enzyme activity leads to buildup of certain chemicals, including sulfite, S-sulfocysteine, xanthine, and hypoxanthine (which can be identified in urine), and low levels of uric acid in the blood. Sulfite, which is normally broken down by one of the molybdenum cofactor-dependent enzymes, is toxic, especially to the brain. Researchers suggest that damage caused by the abnormally high levels of sulfite (and possibly other chemicals) leads to encephalopathy, seizures, and the other features of molybdenum cofactor deficiency.
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Is molybdenum cofactor deficiency inherited ?
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Molybdenum cofactor deficiency has an autosomal recessive pattern of inheritance, which means both copies of the gene in each cell have mutations. An affected individual usually inherits one altered copy of the gene from each parent. Parents of an individual with an autosomal recessive condition typically do not show signs and symptoms of the condition. At least one individual with molybdenum cofactor deficiency inherited two mutated copies of the MOCS1 gene through a mechanism called uniparental isodisomy. In this case, an error occurred during the formation of egg or sperm cells, and the child received two copies of the mutated gene from one parent instead of one copy from each parent.
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What are the treatments for molybdenum cofactor deficiency ?
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These resources address the diagnosis or management of molybdenum cofactor deficiency: - Genetic Testing Registry: Combined molybdoflavoprotein enzyme deficiency - Genetic Testing Registry: Molybdenum cofactor deficiency, complementation group A - Genetic Testing Registry: Molybdenum cofactor deficiency, complementation group B - Genetic Testing Registry: Molybdenum cofactor deficiency, complementation group C These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) thrombotic thrombocytopenic purpura ?
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Thrombotic thrombocytopenic purpura is a rare disorder that causes blood clots (thrombi) to form in small blood vessels throughout the body. These clots can cause serious medical problems if they block vessels and restrict blood flow to organs such as the brain, kidneys, and heart. Resulting complications can include neurological problems (such as personality changes, headaches, confusion, and slurred speech), fever, abnormal kidney function, abdominal pain, and heart problems. Blood clots normally form to prevent excess blood loss at the site of an injury. In people with thrombotic thrombocytopenic purpura, clots develop in blood vessels even in the absence of injury. Blood clots are formed from clumps of cell fragments called platelets, which circulate in the blood and assist with clotting. Because a large number of platelets are used to make clots in people with thrombotic thrombocytopenic purpura, fewer platelets are available in the bloodstream. A reduced level of circulating platelets is known as thrombocytopenia. Thrombocytopenia can lead to small areas of bleeding just under the surface of the skin, resulting in purplish spots called purpura. This disorder also causes red blood cells to break down (undergo hemolysis) prematurely. As blood squeezes past clots within blood vessels, red blood cells can break apart. A condition called hemolytic anemia occurs when red blood cells are destroyed faster than the body can replace them. This type of anemia leads to paleness, yellowing of the eyes and skin (jaundice), fatigue, shortness of breath, and a rapid heart rate. There are two major forms of thrombotic thrombocytopenic purpura, an acquired (noninherited) form and a familial form. The acquired form usually appears in late childhood or adulthood. Affected individuals may have a single episode of signs and symptoms, or they may recur over time. The familial form of this disorder is much rarer and typically appears in infancy or early childhood. In people with the familial form, signs and symptoms often recur on a regular basis.
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How many people are affected by thrombotic thrombocytopenic purpura ?
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The precise incidence of thrombotic thrombocytopenic purpura is unknown. Researchers estimate that, depending on geographic location, the condition affects 1.7 to 11 per million people each year in the United States. For unknown reasons, the disorder occurs more frequently in women than in men. The acquired form of thrombotic thrombocytopenic purpura is much more common than the familial form.
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What are the genetic changes related to thrombotic thrombocytopenic purpura ?
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Mutations in the ADAMTS13 gene cause the familial form of thrombotic thrombocytopenic purpura. The ADAMTS13 gene provides instructions for making an enzyme that is involved in the normal process of blood clotting. Mutations in this gene lead to a severe reduction in the activity of this enzyme. The acquired form of thrombotic thrombocytopenic purpura also results from a reduction in ADAMTS13 enzyme activity; however, people with the acquired form do not have mutations in the ADAMTS13 gene. Instead, their immune systems often produce specific proteins called autoantibodies that block the activity of the enzyme. A lack of ADAMTS13 enzyme activity disrupts the usual balance between bleeding and clotting. Normally, blood clots form at the site of an injury to seal off damaged blood vessels and prevent excess blood loss. In people with thrombotic thrombocytopenic purpura, clots form throughout the body as platelets bind together abnormally and stick to the walls of blood vessels. These clots can block small blood vessels, causing organ damage and the other features of thrombotic thrombocytopenic purpura. Researchers believe that other genetic or environmental factors may contribute to the signs and symptoms of thrombotic thrombocytopenic purpura. In people with reduced ADAMTS13 enzyme activity, factors such as pregnancy, surgery, and infection may trigger abnormal blood clotting and its associated complications.
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Is thrombotic thrombocytopenic purpura inherited ?
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The familial form of thrombotic thrombocytopenic purpura 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. The acquired form of thrombotic thrombocytopenic purpura is not inherited.
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What are the treatments for thrombotic thrombocytopenic purpura ?
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These resources address the diagnosis or management of thrombotic thrombocytopenic purpura: - Genetic Testing Registry: Upshaw-Schulman syndrome - MedlinePlus Encyclopedia: Blood Clots - MedlinePlus Encyclopedia: Hemolytic anemia - MedlinePlus Encyclopedia: Purpura - MedlinePlus Encyclopedia: Thrombocytopenia - MedlinePlus Encyclopedia: Thrombotic thrombocytopenic purpura These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) Muenke syndrome ?
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Muenke syndrome is a condition characterized by the premature closure of certain bones of the skull (craniosynostosis) during development, which affects the shape of the head and face. Many people with this disorder have a premature fusion of skull bones along the coronal suture, the growth line which goes over the head from ear to ear. Other parts of the skull may be malformed as well. These changes can result in an abnormally shaped head, wide-set eyes, and flattened cheekbones. About 5 percent of affected individuals have an enlarged head (macrocephaly). People with Muenke syndrome may also have mild abnormalities of the hands or feet, and hearing loss has been observed in some cases. Most people with this condition have normal intellect, but developmental delay and learning disabilities are possible. The signs and symptoms of Muenke syndrome vary among affected people, and some findings overlap with those seen in other craniosynostosis syndromes. Between 6 percent and 7 percent of people with the gene mutation associated with Muenke syndrome do not have any of the characteristic features of the disorder.
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How many people are affected by Muenke syndrome ?
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Muenke syndrome occurs in about 1 in 30,000 newborns. This condition accounts for an estimated 8 percent of all cases of craniosynostosis.
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What are the genetic changes related to Muenke syndrome ?
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Mutations in the FGFR3 gene cause Muenke syndrome. The FGFR3 gene provides instructions for making a protein that is involved in the development and maintenance of bone and brain tissue. A single mutation in the FGFR3 gene is responsible for Muenke syndrome. This mutation causes the FGFR3 protein to be overly active, which interferes with normal bone growth and allows the bones of the skull to fuse before they should.
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Is Muenke syndrome inherited ?
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This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
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What are the treatments for Muenke syndrome ?
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These resources address the diagnosis or management of Muenke syndrome: - Gene Review: Gene Review: FGFR-Related Craniosynostosis Syndromes - Gene Review: Gene Review: Muenke Syndrome - Genetic Testing Registry: Muenke syndrome - MedlinePlus Encyclopedia: Craniosynostosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) glutaric acidemia type I ?
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Glutaric acidemia type I is an inherited disorder in which the body is unable to process certain proteins properly. People with this disorder have inadequate levels of an enzyme that helps break down the amino acids lysine, hydroxylysine, and tryptophan, which are building blocks of protein. Excessive levels of these amino acids and their intermediate breakdown products can accumulate and cause damage to the brain, particularly the basal ganglia, which are regions that help control movement. Intellectual disability may also occur. The severity of glutaric acidemia type I varies widely; some individuals are only mildly affected, while others have severe problems. In most cases, signs and symptoms first occur in infancy or early childhood, but in a small number of affected individuals, the disorder first becomes apparent in adolescence or adulthood. Some babies with glutaric acidemia type I are born with unusually large heads (macrocephaly). Affected individuals may have difficulty moving and may experience spasms, jerking, rigidity, or decreased muscle tone. Some individuals with glutaric acidemia have developed bleeding in the brain or eyes that could be mistaken for the effects of child abuse. Strict dietary control may help limit progression of the neurological damage. Stress caused by infection, fever or other demands on the body may lead to worsening of the signs and symptoms, with only partial recovery.
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How many people are affected by glutaric acidemia type I ?
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Glutaric acidemia type I occurs in approximately 1 of every 30,000 to 40,000 individuals. It is much more common in the Amish community and in the Ojibwa population of Canada, where up to 1 in 300 newborns may be affected.
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What are the genetic changes related to glutaric acidemia type I ?
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Mutations in the GCDH gene cause glutaric acidemia type I. The GCDH gene provides instructions for making the enzyme glutaryl-CoA dehydrogenase. This enzyme is involved in processing the amino acids lysine, hydroxylysine, and tryptophan. Mutations in the GCDH gene prevent production of the enzyme or result in the production of a defective enzyme that cannot function. This enzyme deficiency allows lysine, hydroxylysine and tryptophan and their intermediate breakdown products to build up to abnormal levels, especially at times when the body is under stress. The intermediate breakdown products resulting from incomplete processing of lysine, hydroxylysine, and tryptophan can damage the brain, particularly the basal ganglia, causing the signs and symptoms of glutaric acidemia type I.
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Is glutaric acidemia type I inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for glutaric acidemia type I ?
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These resources address the diagnosis or management of glutaric acidemia type I: - Baby's First Test - Genetic Testing Registry: Glutaric aciduria, type 1 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) Rubinstein-Taybi syndrome ?
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Rubinstein-Taybi syndrome is a condition characterized by short stature, moderate to severe intellectual disability, distinctive facial features, and broad thumbs and first toes. Additional features of the disorder can include eye abnormalities, heart and kidney defects, dental problems, and obesity. These signs and symptoms vary among affected individuals. People with this condition have an increased risk of developing noncancerous and cancerous tumors, including certain kinds of brain tumors. Cancer of blood-forming tissue (leukemia) also occurs more frequently in people with Rubinstein-Taybi syndrome. Rarely, Rubinstein-Taybi syndrome can involve serious complications such as a failure to gain weight and grow at the expected rate (failure to thrive) and life-threatening infections. Infants born with this severe form of the disorder usually survive only into early childhood.
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How many people are affected by Rubinstein-Taybi syndrome ?
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This condition is uncommon; it occurs in an estimated 1 in 100,000 to 125,000 newborns.
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What are the genetic changes related to Rubinstein-Taybi syndrome ?
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Mutations in the CREBBP gene are responsible for some cases of Rubinstein-Taybi syndrome. The CREBBP gene provides instructions for making a protein that helps control the activity of many other genes. This protein, called CREB binding protein, plays an important role in regulating cell growth and division and is essential for normal fetal development. If one copy of the CREBBP gene is deleted or mutated, cells make only half of the normal amount of CREB binding protein. Although a reduction in the amount of this protein disrupts normal development before and after birth, researchers have not determined how it leads to the specific signs and symptoms of Rubinstein-Taybi syndrome. Mutations in the EP300 gene cause a small percentage of cases of Rubinstein-Taybi syndrome. Like the CREBBP gene, this gene provides instructions for making a protein that helps control the activity of other genes. It also appears to be important for development before and after birth. EP300 mutations inactivate one copy of the gene in each cell, which interferes with normal development and causes the typical features of Rubinstein-Taybi syndrome. The signs and symptoms of this disorder in people with EP300 mutations are similar to those with mutations in the CREBBP gene; however, studies suggest that EP300 mutations may be associated with milder skeletal changes in the hands and feet. Some cases of severe Rubinstein-Taybi syndrome have resulted from a deletion of genetic material from the short (p) arm of chromosome 16. Several genes, including the CREBBP gene, are missing as a result of this deletion. Researchers believe that the loss of multiple genes in this region probably accounts for the serious complications associated with severe Rubinstein-Taybi syndrome. About half of people with Rubinstein-Taybi syndrome do not have an identified mutation in the CREBBP or EP300 gene or a deletion in chromosome 16. The cause of the condition is unknown in these cases. Researchers predict that mutations in other genes are also responsible for the disorder.
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Is Rubinstein-Taybi syndrome inherited ?
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This condition is considered to have an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most cases result from new mutations in the gene and occur in people with no history of the disorder in their family.
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What are the treatments for Rubinstein-Taybi syndrome ?
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These resources address the diagnosis or management of Rubinstein-Taybi syndrome: - Gene Review: Gene Review: Rubinstein-Taybi Syndrome - Genetic Testing Registry: Rubinstein-Taybi syndrome - MedlinePlus Encyclopedia: Rubinstein-Taybi syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) vitelliform macular dystrophy ?
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Vitelliform macular dystrophy is a genetic eye disorder that can cause progressive vision loss. This disorder affects the retina, the specialized light-sensitive tissue that lines the back of the eye. Specifically, vitelliform macular dystrophy disrupts cells in a small area near the center of the retina called the macula. The macula is responsible for sharp central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces. Vitelliform macular dystrophy causes a fatty yellow pigment (lipofuscin) to build up in cells underlying the macula. Over time, the abnormal accumulation of this substance can damage cells that are critical for clear central vision. As a result, people with this disorder often lose their central vision, and their eyesight may become blurry or distorted. Vitelliform macular dystrophy typically does not affect side (peripheral) vision or the ability to see at night. Researchers have described two forms of vitelliform macular dystrophy with similar features. The early-onset form (known as Best disease) usually appears in childhood; the onset of symptoms and the severity of vision loss vary widely. The adult-onset form begins later, usually in mid-adulthood, and tends to cause vision loss that worsens slowly over time. The two forms of vitelliform macular dystrophy each have characteristic changes in the macula that can be detected during an eye examination.
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How many people are affected by vitelliform macular dystrophy ?
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Vitelliform macular dystrophy is a rare disorder; its incidence is unknown.
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What are the genetic changes related to vitelliform macular dystrophy ?
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Mutations in the BEST1 and PRPH2 genes cause vitelliform macular dystrophy. BEST1 mutations are responsible for Best disease and for some cases of the adult-onset form of vitelliform macular dystrophy. Changes in the PRPH2 gene can also cause the adult-onset form of vitelliform macular dystrophy; however, less than a quarter of all people with this form of the condition have mutations in the BEST1 or PRPH2 gene. In most cases, the cause of the adult-onset form is unknown. The BEST1 gene provides instructions for making a protein called bestrophin. This protein acts as a channel that controls the movement of charged chlorine atoms (chloride ions) into or out of cells in the retina. Mutations in the BEST1 gene probably lead to the production of an abnormally shaped channel that cannot properly regulate the flow of chloride. Researchers have not determined how these malfunctioning channels are related to the buildup of lipofuscin in the macula and progressive vision loss. The PRPH2 gene provides instructions for making a protein called peripherin 2. This protein is essential for the normal function of light-sensing (photoreceptor) cells in the retina. Mutations in the PRPH2 gene cause vision loss by disrupting structures in these cells that contain light-sensing pigments. It is unclear why PRPH2 mutations affect only central vision in people with adult-onset vitelliform macular dystrophy.
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Is vitelliform macular dystrophy inherited ?
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Best disease 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. The inheritance pattern of adult-onset vitelliform macular dystrophy is uncertain. Some studies have suggested that this disorder may be inherited in an autosomal dominant pattern. It is difficult to be sure, however, because many affected people have no history of the disorder in their family, and only a small number of affected families have been reported.
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What are the treatments for vitelliform macular dystrophy ?
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These resources address the diagnosis or management of vitelliform macular dystrophy: - Gene Review: Gene Review: Best Vitelliform Macular Dystrophy - Genetic Testing Registry: Macular dystrophy, vitelliform, adult-onset - Genetic Testing Registry: Vitelliform dystrophy - MedlinePlus Encyclopedia: Macula (image) These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) sensorineural deafness and male infertility ?
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Sensorineural deafness and male infertility is a condition characterized by hearing loss and an inability to father children. Affected individuals have moderate to severe sensorineural hearing loss, which is caused by abnormalities in the inner ear. The hearing loss is typically diagnosed in early childhood and does not worsen over time. Males with this condition produce sperm that have decreased movement (motility), causing affected males to be infertile.
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How many people are affected by sensorineural deafness and male infertility ?
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The prevalence of sensorineural deafness and male infertility is unknown.
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What are the genetic changes related to sensorineural deafness and male infertility ?
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Sensorineural deafness and male infertility is caused by a deletion of genetic material on the long (q) arm of chromosome 15. The signs and symptoms of sensorineural deafness and male infertility are related to the loss of multiple genes in this region. The size of the deletion varies among affected individuals. Researchers have determined that the loss of a particular gene on chromosome 15, the STRC gene, is responsible for hearing loss in affected individuals. The loss of another gene, CATSPER2, in the same region of chromosome 15 is responsible for the sperm abnormalities and infertility in affected males. Researchers are working to determine how the loss of additional genes in the deleted region affects people with sensorineural deafness and male infertility.
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Is sensorineural deafness and male infertility inherited ?
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Sensorineural deafness and male infertility is inherited in an autosomal recessive pattern, which means both copies of chromosome 15 in each cell have a deletion. The parents of an individual with sensorineural deafness and male infertility each carry one copy of the chromosome 15 deletion, but they do not show symptoms of the condition. Males with two chromosome 15 deletions in each cell have sensorineural deafness and infertility. Females with two chromosome 15 deletions in each cell have sensorineural deafness as their only symptom because the CATSPER2 gene deletions affect sperm function, and women do not produce sperm.
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What are the treatments for sensorineural deafness and male infertility ?
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These resources address the diagnosis or management of sensorineural deafness and male infertility: - Cleveland Clinic: Male Infertility - Gene Review: Gene Review: CATSPER-Related Male Infertility - Genetic Testing Registry: Deafness, sensorineural, and male infertility - MedlinePlus Health Topic: Assisted Reproductive Technology - RESOLVE: The National Infertility Association: Semen Analysis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) Weill-Marchesani syndrome ?
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Weill-Marchesani syndrome is a disorder of connective tissue. Connective tissue forms the body's supportive framework, providing structure and strength to the muscles, joints, organs, and skin. The major signs and symptoms of Weill-Marchesani syndrome include short stature, eye abnormalities, unusually short fingers and toes (brachydactyly), and joint stiffness. Adult height for men with Weill-Marchesani syndrome ranges from 4 feet, 8 inches to 5 feet, 6 inches. Adult height for women with this condition ranges from 4 feet, 3 inches to 5 feet, 2 inches. An eye abnormality called microspherophakia is characteristic of Weill-Marchesani syndrome. This term refers to a small, sphere-shaped lens, which is associated with nearsightedness (myopia) that worsens over time. The lens also may be positioned abnormally within the eye (ectopia lentis). Many people with Weill-Marchesani syndrome develop glaucoma, an eye disease that increases the pressure in the eye and can lead to blindness. Occasionally, heart defects or an abnormal heart rhythm can occur in people with Weill-Marchesani syndrome.
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How many people are affected by Weill-Marchesani syndrome ?
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Weill-Marchesani syndrome appears to be rare; it has an estimated prevalence of 1 in 100,000 people.
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What are the genetic changes related to Weill-Marchesani syndrome ?
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Mutations in the ADAMTS10 and FBN1 genes can cause Weill-Marchesani syndrome. The ADAMTS10 gene provides instructions for making a protein whose function is unknown. This protein is important for normal growth before and after birth, and it appears to be involved in the development of the eyes, heart, and skeleton. Mutations in this gene disrupt the normal development of these structures, which leads to the specific features of Weill-Marchesani syndrome. A mutation in the FBN1 gene has also been found to cause Weill-Marchesani syndrome. The FBN1 gene provides instructions for making a protein called fibrillin-1. This protein is needed to form threadlike filaments, called microfibrils, that help provide strength and flexibility to connective tissue. The FBN1 mutation responsible for Weill-Marchesani syndrome leads to an unstable version of fibrillin-1. Researchers believe that the unstable protein interferes with the normal assembly of microfibrils, which weakens connective tissue and causes the abnormalities associated with Weill-Marchesani syndrome. In some people with Weill-Marchesani syndrome, no mutations in ADAMTS10 or FBN1 have been found. Researchers are looking for other genetic changes that may be responsible for the disorder in these people.
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Is Weill-Marchesani syndrome inherited ?
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Weill-Marchesani syndrome can be inherited in either an autosomal recessive or an autosomal dominant pattern. When Weill-Marchesani syndrome is caused by mutations in the ADAMTS10 gene, it has an autosomal recessive pattern of inheritance. Autosomal recessive inheritance 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. Other cases of Weill-Marchesani syndrome, including those caused by mutations in the FBN1 gene, have an autosomal dominant pattern of inheritance. 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 genetic change from one parent with the condition.
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What are the treatments for Weill-Marchesani syndrome ?
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These resources address the diagnosis or management of Weill-Marchesani syndrome: - Gene Review: Gene Review: Weill-Marchesani Syndrome - Genetic Testing Registry: Weill-Marchesani syndrome - Genetic Testing Registry: Weill-Marchesani syndrome 1 - Genetic Testing Registry: Weill-Marchesani syndrome 2 - Genetic Testing Registry: Weill-Marchesani syndrome 3 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) Cole disease ?
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Cole disease is a disorder that affects the skin. People with this disorder have areas of unusually light-colored skin (hypopigmentation), typically on the arms and legs, and spots of thickened skin on the palms of the hands and the soles of the feet (punctate palmoplantar keratoderma). These skin features are present at birth or develop in the first year of life. In some cases, individuals with Cole disease develop abnormal accumulations of the mineral calcium (calcifications) in the tendons, which can cause pain during movement. Calcifications may also occur in the skin or breast tissue.
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How many people are affected by Cole disease ?
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Cole disease is a rare disease; its prevalence is unknown. Only a few affected families have been described in the medical literature.
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What are the genetic changes related to Cole disease ?
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Cole disease is caused by mutations in the ENPP1 gene. This gene provides instructions for making a protein that helps to prevent minerals, including calcium, from being deposited in body tissues where they do not belong. It also plays a role in controlling cell signaling in response to the hormone insulin, through interaction between a part of the ENPP1 protein called the SMB2 domain and the insulin receptor. The insulin receptor is a protein that attaches (binds) to insulin and initiates cell signaling. Insulin plays many roles in the body, including regulating blood sugar levels by controlling how much sugar (in the form of glucose) is passed from the bloodstream into cells to be used as energy. Cell signaling in response to insulin is also important for the maintenance of the outer layer of skin (the epidermis). It helps control the transport of the pigment melanin from the cells in which it is produced (melanocytes) to epidermal cells called keratinocytes, and it is also involved in the development of keratinocytes. The mutations that cause Cole disease change the structure of the SMB2 domain, which alters its interaction with the insulin receptor and affects cell signaling. The resulting impairment of ENPP1's role in melanin transport and keratinocyte development leads to the hypopigmentation and keratoderma that occurs in Cole disease. The mutations may also impair ENPP1's control of calcification, which likely accounts for the abnormal calcium deposits that occur in some people with this disorder. For reasons that are unclear, the changes in insulin signaling resulting from these ENPP1 gene mutations do not seem to affect blood sugar control.
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Is Cole disease inherited ?
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This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases of this disorder, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family.
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What are the treatments for Cole disease ?
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These resources address the diagnosis or management of Cole disease: - Genetic Testing Registry: Cole 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
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What is (are) Baraitser-Winter syndrome ?
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Baraitser-Winter syndrome is a condition that affects the development of many parts of the body, particularly the face and the brain. An unusual facial appearance is the most common characteristic of Baraitser-Winter syndrome. Distinctive facial features can include widely spaced eyes (hypertelorism), large eyelid openings, droopy eyelids (ptosis), high-arched eyebrows, a broad nasal bridge and tip of the nose, a long space between the nose and upper lip (philtrum), full cheeks, and a pointed chin. Structural brain abnormalities are also present in most people with Baraitser-Winter syndrome. These abnormalities are related to impaired neuronal migration, a process by which nerve cells (neurons) move to their proper positions in the developing brain. The most frequent brain abnormality associated with Baraitser-Winter syndrome is pachygyria, which is an area of the brain that has an abnormally smooth surface with fewer folds and grooves. Less commonly, affected individuals have lissencephaly, which is similar to pachygyria but involves the entire brain surface. These structural changes can cause mild to severe intellectual disability, developmental delay, and seizures. Other features of Baraitser-Winter syndrome can include short stature, ear abnormalities and hearing loss, heart defects, presence of an extra (duplicated) thumb, and abnormalities of the kidneys and urinary system. Some affected individuals have limited movement of large joints, such as the elbows and knees, which may be present at birth or develop over time. Rarely, people with Baraitser-Winter syndrome have involuntary muscle tensing (dystonia).
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How many people are affected by Baraitser-Winter syndrome ?
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Baraitser-Winter syndrome is a rare condition. Fewer than 50 cases have been reported in the medical literature.
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What are the genetic changes related to Baraitser-Winter syndrome ?
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Baraitser-Winter syndrome can result from mutations in either the ACTB or ACTG1 gene. These genes provide instructions for making proteins called beta ()-actin and gamma ()-actin, respectively. These proteins are active (expressed) in cells throughout the body. They are organized into a network of fibers called the actin cytoskeleton, which makes up the cell's structural framework. The actin cytoskeleton has several critical functions, including determining cell shape and allowing cells to move. Mutations in the ACTB or ACTG1 gene alter the function of -actin or -actin. The malfunctioning actin causes changes in the actin cytoskeleton that modify the structure and organization of cells and affect their ability to move. Because these two actin proteins are present in cells throughout the body and are involved in many cell activities, problems with their function likely impact many aspects of development, including neuronal migration. These changes underlie the variety of signs and symptoms associated with Baraitser-Winter syndrome.
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Is Baraitser-Winter syndrome inherited ?
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This condition is described as autosomal dominant, which means one copy of the altered gene in each cell is sufficient to cause the disorder. The condition almost always results from new (de novo) mutations in the ACTB or ACTG1 gene and occurs in people with no history of the disorder in their family.
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What are the treatments for Baraitser-Winter syndrome ?
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These resources address the diagnosis or management of Baraitser-Winter syndrome: - Gene Review: Gene Review: Baraitser-Winter Cerebrofrontofacial Syndrome - Genetic Testing Registry: Baraitser-Winter Syndrome 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
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What is (are) X-linked lymphoproliferative disease ?
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X-linked lymphoproliferative disease (XLP) is a disorder of the immune system and blood-forming cells that is found almost exclusively in males. More than half of individuals with this disorder experience an exaggerated immune response to the Epstein-Barr virus (EBV). EBV is a very common virus that eventually infects most humans. In some people it causes infectious mononucleosis (commonly known as "mono"). Normally, after initial infection, EBV remains in certain immune system cells (lymphocytes) called B cells. However, the virus is generally inactive (latent) because it is controlled by other lymphocytes called T cells that specifically target EBV-infected B cells. People with XLP may respond to EBV infection by producing abnormally large numbers of T cells, B cells, and other lymphocytes called macrophages. This proliferation of immune cells often causes a life-threatening reaction called hemophagocytic lymphohistiocytosis. Hemophagocytic lymphohistiocytosis causes fever, destroys blood-producing cells in the bone marrow, and damages the liver. The spleen, heart, kidneys, and other organs and tissues may also be affected. In some individuals with XLP, hemophagocytic lymphohistiocytosis or related symptoms may occur without EBV infection. About one-third of people with XLP experience dysgammaglobulinemia, which means they have abnormal levels of some types of antibodies. Antibodies (also known as immunoglobulins) are proteins that attach to specific foreign particles and germs, marking them for destruction. Individuals with dysgammaglobulinemia are prone to recurrent infections. Cancers of immune system cells (lymphomas) occur in about one-third of people with XLP. Without treatment, most people with XLP survive only into childhood. Death usually results from hemophagocytic lymphohistiocytosis. XLP can be divided into two types based on its genetic cause and pattern of signs and symptoms: XLP1 (also known as classic XLP) and XLP2. People with XLP2 have not been known to develop lymphoma, are more likely to develop hemophagocytic lymphohistiocytosis without EBV infection, usually have an enlarged spleen (splenomegaly), and may also have inflammation of the large intestine (colitis). Some researchers believe that these individuals should actually be considered to have a similar but separate disorder rather than a type of XLP.
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How many people are affected by X-linked lymphoproliferative disease ?
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XLP1 is estimated to occur in about 1 per million males worldwide. XLP2 is less common, occurring in about 1 per 5 million males.
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What are the genetic changes related to X-linked lymphoproliferative disease ?
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Mutations in the SH2D1A and XIAP genes cause XLP. SH2D1A gene mutations cause XLP1, and XIAP gene mutations cause XLP2. The SH2D1A gene provides instructions for making a protein called signaling lymphocyte activation molecule (SLAM) associated protein (SAP). This protein is involved in the functioning of lymphocytes that destroy other cells (cytotoxic lymphocytes) and is necessary for the development of specialized T cells called natural killer T cells. The SAP protein also helps control immune reactions by triggering self-destruction (apoptosis) of cytotoxic lymphocytes when they are no longer needed. Some SH2D1A gene mutations impair SAP function. Others result in an abnormally short protein that is unstable or nonfunctional, or prevent any SAP from being produced. The loss of functional SAP disrupts proper signaling in the immune system and may prevent the body from controlling the immune reaction to EBV infection. In addition, lymphomas may develop when defective lymphocytes are not properly destroyed by apoptosis. The XIAP gene provides instructions for making a protein that helps protect cells from undergoing apoptosis in response to certain signals. XIAP gene mutations can lead to an absence of XIAP protein or decrease the amount of XIAP protein that is produced. It is unknown how a lack of XIAP protein results in the signs and symptoms of XLP, or why features of this disorder differ somewhat between people with XIAP and SH2D1A gene mutations.
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Is X-linked lymphoproliferative disease inherited ?
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This condition is generally inherited in an X-linked recessive pattern. The genes associated with this condition are 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 an associated gene in each cell is sufficient to cause the condition. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In females (who have two X chromosomes), a mutation usually has to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of an associated gene, males are affected by X-linked recessive disorders much more frequently than females. However, in rare cases a female carrying one altered copy of the SH2D1A or XIAP gene in each cell may develop signs and symptoms of this condition.
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What are the treatments for X-linked lymphoproliferative disease ?
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These resources address the diagnosis or management of XLP: - Children's Hospital of Philadelphia - Gene Review: Gene Review: Lymphoproliferative Disease, X-Linked - Genetic Testing Registry: Lymphoproliferative syndrome 1, X-linked - Genetic Testing Registry: Lymphoproliferative syndrome 2, X-linked - MedlinePlus Encyclopedia: Epstein-Barr Virus Test - Merck Manual for Healthcare Professionals - XLP Research Trust: Immunoglobulin Replacement - XLP Research Trust: Preparing for Bone Marrow Transplant These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) malignant migrating partial seizures of infancy ?
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Malignant migrating partial seizures of infancy (MMPSI) is a severe form of epilepsy that begins very early in life. Recurrent seizures begin before the age of 6 months but commonly start within a few weeks of birth. The seizures do not respond well to treatment. Although affected individuals may develop normally at first, progression stalls and skills decline when seizures begin; as a result, affected individuals have profound developmental delay. The seizures in MMPSI are described as partial (or focal) because the seizure activity occurs in regions of the brain rather than affecting the entire brain. Seizure activity can appear in multiple locations in the brain or move (migrate) from one region to another during an episode. Depending on the region affected, seizures can involve sudden redness and warmth (flushing) of the face; drooling; short pauses in breathing (apnea); movement of the head or eyes to one side; twitches in the eyelids or tongue; chewing motions; or jerking of an arm, leg, or both on one side of the body. If seizure activity spreads to affect the entire brain, it causes a loss of consciousness, muscle stiffening, and rhythmic jerking (tonic-clonic seizure). Episodes that begin as partial seizures and spread throughout the brain are known as secondarily generalized seizures. Initially, the seizures associated with MMPSI are relatively infrequent, occurring every few weeks. Within a few months of the seizures starting, though, the frequency increases. Affected individuals can have clusters of five to 30 seizures several times a day. Each seizure typically lasts seconds to a couple of minutes, but they can be prolonged (classified as status epilepticus). In some cases, the seizure activity may be almost continuous for several days. After a year or more of persistent seizures, the episodes become less frequent. Seizures can affect growth of the brain and lead to a small head size (microcephaly). The problems with brain development can also cause profound developmental delay and intellectual impairment. Affected babies often lose the mental and motor skills they developed after birth, such as the ability to make eye contact and control their head movement. Many have weak muscle tone (hypotonia) and become "floppy." If seizures can be controlled for a short period, development may improve. Some affected children learn to reach for objects or walk. However, most children with this condition do not develop language skills. Because of the serious health problems caused by MMPSI, many affected individuals do not survive past infancy or early childhood.
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How many people are affected by malignant migrating partial seizures of infancy ?
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MMPSI is a rare condition. Although its prevalence is unknown, approximately 100 cases have been described in the medical literature.
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What are the genetic changes related to malignant migrating partial seizures of infancy ?
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The genetic cause of MMPSI is not fully known. Mutations in the KCNT1 gene have been found in several individuals with this condition and are the most common known cause of MMPSI. Mutations in other genes are also thought to be involved in the condition. The KCNT1 gene provides instructions for making a protein that forms potassium channels. Potassium channels, which transport positively charged atoms (ions) of potassium into and out of cells, play a key role in a cell's ability to generate and transmit electrical signals. Channels made with the KCNT1 protein are active in nerve cells (neurons) in the brain, where they transport potassium ions out of cells. This flow of ions is involved in generating currents to activate (excite) neurons and send signals in the brain. KCNT1 gene mutations alter the KCNT1 protein. Electrical currents generated by potassium channels made with the altered KCNT1 protein are abnormally increased, which allows unregulated excitation of neurons in the brain. Seizures develop when neurons in the brain are abnormally excited. It is unclear why seizure activity can migrate in MMPSI. Repeated seizures in affected individuals contribute to the developmental delay that is characteristic of this condition.
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Is malignant migrating partial seizures of infancy inherited ?
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MMPSI is not inherited from a parent and does not run in families. This condition is caused by a new mutation that occurs very early in embryonic development (called a de novo mutation).
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What are the treatments for malignant migrating partial seizures of infancy ?
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These resources address the diagnosis or management of malignant migrating partial seizures of infancy: - Genetic Testing Registry: Early infantile epileptic encephalopathy 14 - MedlinePlus Encyclopedia: EEG These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) alpha-1 antitrypsin deficiency ?
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Alpha-1 antitrypsin deficiency is an inherited disorder that may cause lung disease and liver disease. The signs and symptoms of the condition and the age at which they appear vary among individuals. People with alpha-1 antitrypsin deficiency usually develop the first signs and symptoms of lung disease between ages 20 and 50. The earliest symptoms are shortness of breath following mild activity, reduced ability to exercise, and wheezing. Other signs and symptoms can include unintentional weight loss, recurring respiratory infections, fatigue, and rapid heartbeat upon standing. Affected individuals often develop emphysema, which is a lung disease caused by damage to the small air sacs in the lungs (alveoli). Characteristic features of emphysema include difficulty breathing, a hacking cough, and a barrel-shaped chest. Smoking or exposure to tobacco smoke accelerates the appearance of emphysema symptoms and damage to the lungs. About 10 percent of infants with alpha-1 antitrypsin deficiency develop liver disease, which often causes yellowing of the skin and whites of the eyes (jaundice). Approximately 15 percent of adults with alpha-1 antitrypsin deficiency develop liver damage (cirrhosis) due to the formation of scar tissue in the liver. Signs of cirrhosis include a swollen abdomen, swollen feet or legs, and jaundice. Individuals with alpha-1 antitrypsin deficiency are also at risk of developing a type of liver cancer called hepatocellular carcinoma. In rare cases, people with alpha-1 antitrypsin deficiency develop a skin condition called panniculitis, which is characterized by hardened skin with painful lumps or patches. Panniculitis varies in severity and can occur at any age.
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How many people are affected by alpha-1 antitrypsin deficiency ?
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Alpha-1 antitrypsin deficiency occurs worldwide, but its prevalence varies by population. This disorder affects about 1 in 1,500 to 3,500 individuals with European ancestry. It is uncommon in people of Asian descent. Many individuals with alpha-1 antitrypsin deficiency are likely undiagnosed, particularly people with a lung condition called chronic obstructive pulmonary disease (COPD). COPD can be caused by alpha-1 antitrypsin deficiency; however, the alpha-1 antitrypsin deficiency is often never diagnosed. Some people with alpha-1 antitrypsin deficiency are misdiagnosed with asthma.
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What are the genetic changes related to alpha-1 antitrypsin deficiency ?
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Mutations in the SERPINA1 gene cause alpha-1 antitrypsin deficiency. This gene provides instructions for making a protein called alpha-1 antitrypsin, which protects the body from a powerful enzyme called neutrophil elastase. Neutrophil elastase is released from white blood cells to fight infection, but it can attack normal tissues (especially the lungs) if not tightly controlled by alpha-1 antitrypsin. Mutations in the SERPINA1 gene can lead to a shortage (deficiency) of alpha-1 antitrypsin or an abnormal form of the protein that cannot control neutrophil elastase. Without enough functional alpha-1 antitrypsin, neutrophil elastase destroys alveoli and causes lung disease. Abnormal alpha-1 antitrypsin can also accumulate in the liver and damage this organ. Environmental factors, such as exposure to tobacco smoke, chemicals, and dust, likely impact the severity of alpha-1 antitrypsin deficiency.
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Is alpha-1 antitrypsin deficiency inherited ?
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This condition is inherited in an autosomal codominant pattern. Codominance means that two different versions of the gene may be active (expressed), and both versions contribute to the genetic trait. The most common version (allele) of the SERPINA1 gene, called M, produces normal levels of alpha-1 antitrypsin. Most people in the general population have two copies of the M allele (MM) in each cell. Other versions of the SERPINA1 gene lead to reduced levels of alpha-1 antitrypsin. For example, the S allele produces moderately low levels of this protein, and the Z allele produces very little alpha-1 antitrypsin. Individuals with two copies of the Z allele (ZZ) in each cell are likely to have alpha-1 antitrypsin deficiency. Those with the SZ combination have an increased risk of developing lung diseases (such as emphysema), particularly if they smoke. Worldwide, it is estimated that 161 million people have one copy of the S or Z allele and one copy of the M allele in each cell (MS or MZ). Individuals with an MS (or SS) combination usually produce enough alpha-1 antitrypsin to protect the lungs. People with MZ alleles, however, have a slightly increased risk of impaired lung or liver function.
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What are the treatments for alpha-1 antitrypsin deficiency ?
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These resources address the diagnosis or management of alpha-1 antitrypsin deficiency: - Alpha-1 Foundation: Testing for Alpha-1 - Cleveland Clinic Respiratory Institute - Gene Review: Gene Review: Alpha-1 Antitrypsin Deficiency - GeneFacts: Alpha-1 Antitrypsin Deficiency: Diagnosis - GeneFacts: Alpha-1 Antitrypsin Deficiency: Management - Genetic Testing Registry: Alpha-1-antitrypsin deficiency - MedlinePlus Encyclopedia: Alpha-1 antitrypsin deficiency - MedlinePlus Encyclopedia: Pulmonary function tests - MedlinePlus Encyclopedia: Wheezing These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) spastic paraplegia type 11 ?
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Spastic paraplegia type 11 is part of a group of genetic disorders known as hereditary spastic paraplegias. These disorders are characterized by progressive muscle stiffness (spasticity) and the development of paralysis of the lower limbs (paraplegia). Hereditary spastic paraplegias are divided into two types: pure and complex. The pure types involve the lower limbs. The complex types involve the lower limbs and can affect the upper limbs to a lesser degree. Complex spastic paraplegias also affect the structure or functioning of the brain and the peripheral nervous system, which consists of nerves connecting the brain and spinal cord to muscles and sensory cells that detect sensations such as touch, pain, heat, and sound. Spastic paraplegia type 11 is a complex hereditary spastic paraplegia. Like all hereditary spastic paraplegias, spastic paraplegia type 11 involves spasticity of the leg muscles and muscle weakness. In almost all individuals with this type of spastic paraplegia, the tissue connecting the left and right halves of the brain (corpus callosum) is abnormally thin. People with this form of spastic paraplegia can also experience numbness, tingling, or pain in the arms and legs (sensory neuropathy); disturbance in the nerves used for muscle movement (motor neuropathy); intellectual disability; exaggerated reflexes (hyperreflexia) of the lower limbs; speech difficulties (dysarthria); reduced bladder control; and muscle wasting (amyotrophy). Less common features include difficulty swallowing (dysphagia), high-arched feet (pes cavus), an abnormal curvature of the spine (scoliosis), and involuntary movements of the eyes (nystagmus). The onset of symptoms varies greatly; however, abnormalities in muscle tone and difficulty walking usually become noticeable in adolescence. Many features of spastic paraplegia type 11 are progressive. Most people experience a decline in intellectual ability and an increase in muscle weakness and nerve abnormalities over time. As the condition progresses, some people require wheelchair assistance.
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How many people are affected by spastic paraplegia type 11 ?
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Over 100 cases of spastic paraplegia type 11 have been reported. Although this condition is thought to be rare, its exact prevalence is unknown.
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What are the genetic changes related to spastic paraplegia type 11 ?
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Mutations in the SPG11 gene cause spastic paraplegia type 11. The SPG11 gene provides instructions for making the protein spatacsin. Spatacsin is active (expressed) throughout the nervous system, although its exact function is unknown. Researchers speculate that spatacsin may be involved in the maintenance of axons, which are specialized extensions of nerve cells (neurons) that transmit impulses throughout the nervous system. SPG11 gene mutations typically change the structure of the spatacsin protein. The effect that the altered spatacsin protein has on the nervous system is not known. Researchers suggest that mutations in spatacsin may cause the signs and symptoms of spastic paraplegia type 11 by interfering with the protein's proposed role in the maintenance of axons.
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Is spastic paraplegia type 11 inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for spastic paraplegia type 11 ?
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These resources address the diagnosis or management of spastic paraplegia type 11: - Gene Review: Gene Review: Spastic Paraplegia 11 - Genetic Testing Registry: Spastic paraplegia 11, autosomal recessive - Spastic Paraplegia Foundation, Inc.: Treatments and Therapies These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) African iron overload ?
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African iron overload is a condition that involves absorption of too much iron from the diet. The excess iron is stored in the body's tissues and organs, particularly the liver, bone marrow, and spleen. Humans cannot increase the excretion of iron, although some iron is lost through bleeding or when cells of the intestine (enterocytes) are shed at the end of the cells' lifespan. Iron levels in the body are primarily regulated through control of how much iron is absorbed from the diet. African iron overload results from a diet high in iron. It is particularly associated with consumption of a traditional African beer that contains dissolved iron from the metal drums in which it is brewed. Some evidence suggests that a genetic predisposition to absorbing too much iron may also be involved. In African iron overload, excess iron typically accumulates in liver cells (hepatocytes) and certain immune cells called reticuloendothelial cells. Reticuloendothelial cells include macrophages in the bone marrow and spleen and Kuppfer cells, which are specialized macrophages found in the liver. Kuppfer cells and other macrophages help protect the body against foreign invaders such as viruses and bacteria. When too much iron is absorbed, the resulting iron overload can eventually damage tissues and organs. Iron overload in the liver may lead to chronic liver disease (cirrhosis) in people with African iron overload. Cirrhosis increases the risk for developing a type of liver cancer called hepatocellular carcinoma. Iron overload in immune cells may affect their ability to fight infections. African iron overload is associated with an increased risk of developing infections such as tuberculosis. People with African iron overload may have a slightly low number of red blood cells (mild anemia), possibly because the iron that accumulates in the liver, bone marrow, and spleen is less available for production of red blood cells. Affected individuals also have high levels of a protein called ferritin in their blood, which can be detected with a blood test. Ferritin stores and releases iron in cells, and cells produce more ferritin in response to excess amounts of iron.
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How many people are affected by African iron overload ?
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African iron overload is common in rural areas of central and southern Africa; up to 10 percent of the population in these regions may be affected. Men seem to be affected more often than women, possibly due to some combination of differences in dietary iron consumption and gender differences in the processing of iron. The prevalence of increased iron stores in people of African descent in other parts of the world is unknown; however, these individuals may be at higher risk of developing mildly increased iron stores than are people of European background.
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What are the genetic changes related to African iron overload ?
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African iron overload was first noted in rural central and southern African populations among people who drink a traditional beer brewed in uncoated steel drums that allow iron (a component of steel) to leach into the beer. However, not all individuals who drink the beer develop African iron overload, and not all individuals of African descent with iron overload drink the beer. Therefore, researchers are seeking genetic differences that affect the risk of developing this condition. Some studies have indicated that a variation in the SLC40A1 gene increases the risk of developing increased iron stores in people of African descent. This variation is found in 5 to 20 percent of people of African descent but is not generally found in other populations. The SLC40A1 gene provides instructions for making a protein called ferroportin. This protein is involved in the process of iron absorption in the body. Iron from the diet is absorbed through the walls of the small intestine. Ferroportin then transports iron from the small intestine into the bloodstream, and the iron is carried by the blood to the tissues and organs of the body. Ferroportin also transports iron out of reticuloendothelial cells in the liver, spleen, and bone marrow. The amount of iron absorbed by the body depends on the amount of iron stored and released from intestinal cells and macrophages. The SLC40A1 gene variation that some studies have associated with increased iron stores in people of African descent may affect the way ferroportin helps to regulate iron absorption in the body. However, researchers suggest that this variation is not associated with most cases of African iron overload.
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Is African iron overload inherited ?
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African iron overload seems to run in families, and high iron in a family's diet seems to be the major contributor to development of the condition. There also may be a genetic contribution, but the inheritance pattern is unknown. People with a specific variation in the SLC40A1 gene may inherit an increased risk of this condition, but not the condition itself. Not all people with this condition have the variation in the gene, and not all people with the variation will develop the disorder.
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What are the treatments for African iron overload ?
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These resources address the diagnosis or management of African iron overload: - Genetic Testing Registry: African nutritional hemochromatosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) aromatase deficiency ?
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Aromatase deficiency is a condition characterized by reduced levels of the female sex hormone estrogen and increased levels of the male sex hormone testosterone. Females with aromatase deficiency have a typical female chromosome pattern (46,XX) but are born with external genitalia that do not appear clearly female or male (ambiguous genitalia). These individuals typically have normal internal reproductive organs, but develop ovarian cysts early in childhood, which impair the release of egg cells from the ovaries (ovulation). In adolescence, most affected females do not develop secondary sexual characteristics, such as breast growth and menstrual periods. They tend to develop acne and excessive body hair growth (hirsutism). Men with this condition have a typical male chromosome pattern (46,XY) and are born with male external genitalia. Some men with this condition have decreased sex drive, abnormal sperm production, or testes that are small or undescended (cryptorchidism). There are other features associated with aromatase deficiency that can affect both males and females. Affected individuals are abnormally tall because of excessive growth of long bones in the arms and legs. The abnormal bone growth results in slowed mineralization of bones (delayed bone age) and thinning of the bones (osteoporosis), which can lead to bone fractures with little trauma. Males and females with aromatase deficiency can have abnormally high blood sugar (hyperglycemia) because the body does not respond correctly to the hormone insulin. In addition, they can have excessive weight gain and a fatty liver. Women who are pregnant with fetuses that have aromatase deficiency often experience mild symptoms of the disorder even though they themselves do not have the disorder. These women may develop hirsutism, acne, an enlarged clitoris (clitoromegaly), and a deep voice. These features can appear as early as 12 weeks of pregnancy and go away soon after delivery.
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How many people are affected by aromatase deficiency ?
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The prevalence of aromatase deficiency is unknown; approximately 20 cases have been described in the medical literature.
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What are the genetic changes related to aromatase deficiency ?
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Mutations in the CYP19A1 gene cause aromatase deficiency. The CYP19A1 gene provides instructions for making an enzyme called aromatase. This enzyme converts a class of hormones called androgens, which are involved in male sexual development, to different forms of estrogen. In females, estrogen guides female sexual development before birth and during puberty. In both males and females, estrogen plays a role in regulating bone growth and blood sugar levels. During fetal development, aromatase converts androgens to estrogens in the placenta, which is the link between the mother's blood supply and the fetus. This conversion in the placenta prevents androgens from directing sexual development in female fetuses. After birth, the conversion of androgens to estrogens takes place in multiple tissues. CYP19A1 gene mutations that cause aromatase deficiency decrease or eliminate aromatase activity. A shortage of functional aromatase results in an inability to convert androgens to estrogens before birth and throughout life. As a result, there is a decrease in estrogen production and an increase in the levels of androgens, including testosterone. In affected individuals, these abnormal hormone levels lead to impaired female sexual development, unusual bone growth, insulin resistance, and other signs and symptoms of aromatase deficiency. In women who are pregnant with an affected fetus, excess androgens in the placenta pass into the woman's bloodstream, which may cause her to have temporary signs and symptoms of aromatase deficiency.
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Is aromatase deficiency inherited ?
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This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
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What are the treatments for aromatase deficiency ?
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These resources address the diagnosis or management of aromatase deficiency: - Genetic Testing Registry: Aromatase deficiency - MedlinePlus Encyclopedia: Ovarian Overproduction of Androgens These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
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What is (are) neonatal onset multisystem inflammatory disease ?
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Neonatal onset multisystem inflammatory disease (NOMID) is a disorder that causes persistent inflammation and tissue damage primarily affecting the nervous system, skin, and joints. Recurrent episodes of mild fever may also occur in this disorder. People with NOMID have a skin rash that is usually present from birth. The rash persists throughout life, although it changes in size and location. Affected individuals often have headaches, seizures, and vomiting resulting from chronic meningitis, which is inflammation of the tissue that covers and protects the brain and spinal cord (meninges). Intellectual disability may occur in some people with this disorder. Hearing and vision problems may result from nerve damage and inflammation in various tissues of the eyes. People with NOMID experience joint inflammation, swelling, and cartilage overgrowth, causing characteristic prominent knees and other skeletal abnormalities that worsen over time. Joint deformities called contractures may restrict the movement of certain joints. Other features of this disorder include short stature with shortening of the lower legs and forearms, and characteristic facial features such as a prominent forehead and protruding eyes. Abnormal deposits of a protein called amyloid (amyloidosis) may cause progressive kidney damage.
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How many people are affected by neonatal onset multisystem inflammatory disease ?
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NOMID is a very rare disorder; approximately 100 affected individuals have been reported worldwide.
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