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genetic changes | What are the genetic changes related to triple A syndrome ? | Mutations in the AAAS gene cause triple A syndrome. This gene provides instructions for making a protein called ALADIN whose function is not well understood. Within cells, ALADIN is found in the nuclear envelope, the structure that surrounds the nucleus and separates it from the rest of the cell. Based on its location, ALADIN is thought to be involved in the movement of molecules into and out of the nucleus. Mutations in the AAAS gene change the structure of ALADIN in different ways; however, almost all mutations prevent this protein from reaching its proper location in the nuclear envelope. The absence of ALADIN in the nuclear envelope likely disrupts the movement of molecules across this membrane. Researchers suspect that DNA repair proteins may be unable to enter the nucleus if ALADIN is missing from the nuclear envelope. DNA damage that is not repaired can cause the cell to become unstable and lead to cell death. Although the nervous system is particularly vulnerable to DNA damage, it remains unknown exactly how mutations in the AAAS gene lead to the signs and symptoms of triple A syndrome. Some individuals with triple A syndrome do not have an identified mutation in the AAAS gene. The genetic cause of the disorder is unknown in these individuals. |
inheritance | Is triple A syndrome inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for triple A syndrome ? | These resources address the diagnosis or management of triple A syndrome: - Genetic Testing Registry: Glucocorticoid deficiency with achalasia - MedlinePlus Encyclopedia: Achalasia - MedlinePlus Encyclopedia: Anisocoria These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) ichthyosis with confetti ? | Ichthyosis with confetti is a disorder of the skin. Individuals with this condition are born with red, scaly skin all over the body, which can be itchy in some people. In childhood or adolescence, hundreds to thousands of small patches of normal skin appear, usually on the torso. The numerous pale spots surrounded by red skin look like confetti, giving the condition its name. The patches of normal skin increase in number and size over time. In addition to red, scaly skin, people with ichthyosis with confetti typically have abnormally thick skin on the palms of the hands and soles of the feet (palmoplantar keratoderma). Many affected individuals have excess hair (hirsutism) on some parts of the body, particularly on the arms and legs. Because of their skin abnormalities, people with ichthyosis with confetti are at increased risk of developing skin infections. |
frequency | How many people are affected by ichthyosis with confetti ? | Ichthyosis with confetti is a rare disorder. Fewer than 20 affected individuals have been described in the medical literature. |
genetic changes | What are the genetic changes related to ichthyosis with confetti ? | Mutations in the KRT10 gene cause ichthyosis with confetti. This gene provides instructions for making a protein called keratin 10, which is found in cells called keratinocytes in the outer layer of the skin (the epidermis). In the fluid-filled space inside these cells (the cytoplasm), this tough, fibrous protein attaches to another keratin protein (produced from a different gene) to form fibers called intermediate filaments. These filaments assemble into strong networks that provide strength and resiliency to the skin. KRT10 gene mutations associated with ichthyosis with confetti alter the keratin 10 protein. The altered protein is abnormally transported to the nucleus of cells, where it cannot form networks of intermediate filaments. Loss of these networks disrupts the epidermis, contributing to the red, scaly skin. However, in some abnormal cells, the mutated gene corrects itself through a complex process by which genetic material is exchanged between chromosomes. As a result, normal keratin 10 protein is produced and remains in the cytoplasm. The cell becomes normal and, as it continues to grow and divide, forms small patches of normal skin that give ichthyosis with confetti its name. |
inheritance | Is ichthyosis with confetti inherited ? | Ichthyosis with confetti 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. Usually, the condition is caused by a new mutation that occurs very early in embryonic development (called a de novo mutation). In these cases, the affected individuals have no history of the disorder in their family. In some cases, an affected person inherits the mutation from one affected parent. |
treatment | What are the treatments for ichthyosis with confetti ? | These resources address the diagnosis or management of ichthyosis with confetti: - Foundation for Ichthyosis and Related Skin Types (FIRST): Skin Care Tips - Foundation for Ichthyosis and Related Skin Types (FIRST): Treating Ichthyosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) congenital leptin deficiency ? | Congenital leptin deficiency is a condition that causes severe obesity beginning in the first few months of life. Affected individuals are of normal weight at birth, but they are constantly hungry and quickly gain weight. Without treatment, the extreme hunger continues and leads to chronic excessive eating (hyperphagia) and obesity. Beginning in early childhood, affected individuals develop abnormal eating behaviors such as fighting with other children over food, hoarding food, and eating in secret. People with congenital leptin deficiency also have hypogonadotropic hypogonadism, which is a condition caused by reduced production of hormones that direct sexual development. Without treatment, affected individuals experience delayed puberty or do not go through puberty, and may be unable to conceive children (infertile). |
frequency | How many people are affected by congenital leptin deficiency ? | Congenital leptin deficiency is a rare disorder. Only a few dozen cases have been reported in the medical literature. |
genetic changes | What are the genetic changes related to congenital leptin deficiency ? | Congenital leptin deficiency is caused by mutations in the LEP gene. This gene provides instructions for making a hormone called leptin, which is involved in the regulation of body weight. Normally, the body's fat cells release leptin in proportion to their size. As fat accumulates in cells, more leptin is produced. This rise in leptin indicates that fat stores are increasing. Leptin attaches (binds) to and activates a protein called the leptin receptor, fitting into the receptor like a key into a lock. The leptin receptor protein is found on the surface of cells in many organs and tissues of the body including a part of the brain called the hypothalamus. The hypothalamus controls hunger and thirst as well as other functions such as sleep, moods, and body temperature. It also regulates the release of many hormones that have functions throughout the body. In the hypothalamus, the binding of leptin to its receptor triggers a series of chemical signals that affect hunger and help produce a feeling of fullness (satiety). LEP gene mutations that cause congenital leptin deficiency lead to an absence of leptin. As a result, the signaling that triggers feelings of satiety does not occur, leading to the excessive hunger and weight gain associated with this disorder. Because hypogonadotropic hypogonadism occurs in congenital leptin deficiency, researchers suggest that leptin signaling is also involved in regulating the hormones that control sexual development. However, the specifics of this involvement and how it may be altered in congenital leptin deficiency are unknown. Congenital leptin deficiency is a rare cause of obesity. Researchers are studying the factors involved in more common forms of obesity. |
inheritance | Is congenital leptin deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for congenital leptin deficiency ? | These resources address the diagnosis or management of congenital leptin deficiency: - Eunice Kennedy Shriver National Institute of Child Health and Human Development: How Are Obesity and Overweight Diagnosed? - Genetic Testing Registry: Obesity, severe, due to leptin deficiency - Genetics of Obesity Study - National Heart, Lung, and Blood Institute: How Are Overweight and Obesity Treated? These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) erythromelalgia ? | Erythromelalgia is a condition characterized by episodes of pain, redness, and swelling in various parts of the body, particularly the hands and feet. These episodes are usually triggered by increased body temperature, which may be caused by exercise or entering a warm room. Ingesting alcohol or spicy foods may also trigger an episode. Wearing warm socks, tight shoes, or gloves can cause a pain episode so debilitating that it can impede everyday activities such as wearing shoes and walking. Pain episodes can prevent an affected person from going to school or work regularly. The signs and symptoms of erythromelalgia typically begin in childhood, although mildly affected individuals may have their first pain episode later in life. As individuals with erythromelalgia get older and the disease progresses, the hands and feet may be constantly red, and the affected areas can extend from the hands to the arms, shoulders, and face, and from the feet to the entire legs. Erythromelalgia is often considered a form of peripheral neuropathy because it affects the peripheral nervous system, which connects the brain and spinal cord to muscles and to cells that detect sensations such as touch, smell, and pain. |
frequency | How many people are affected by erythromelalgia ? | The prevalence of erythromelalgia is unknown. |
genetic changes | What are the genetic changes related to erythromelalgia ? | Mutations in the SCN9A gene can cause erythromelalgia. The SCN9A gene provides instructions for making one part (the alpha subunit) of a sodium channel called NaV1.7. Sodium channels transport positively charged sodium atoms (sodium ions) into cells and play a key role in a cell's ability to generate and transmit electrical signals. NaV1.7 sodium channels are found in nerve cells called nociceptors that transmit pain signals to the spinal cord and brain. The SCN9A gene mutations that cause erythromelalgia result in NaV1.7 sodium channels that open more easily than usual and stays open longer than normal, increasing the flow of sodium ions into nociceptors. This increase in sodium ions enhances transmission of pain signals, leading to the signs and symptoms of erythromelalgia. It is unknown why the pain episodes associated with erythromelalgia mainly occur in the hands and feet. An estimated 15 percent of cases of erythromelalgia are caused by mutations in the SCN9A gene. Other cases are thought to have a nongenetic cause or may be caused by mutations in one or more as-yet unidentified genes. |
inheritance | Is erythromelalgia inherited ? | Some cases of erythromelalgia occur in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some of these instances, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family. |
treatment | What are the treatments for erythromelalgia ? | These resources address the diagnosis or management of erythromelalgia: - Gene Review: Gene Review: SCN9A-Related Inherited Erythromelalgia - Genetic Testing Registry: Primary erythromelalgia These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) glucose phosphate isomerase deficiency ? | Glucose phosphate isomerase (GPI) deficiency is an inherited disorder that affects red blood cells, which carry oxygen to the body's tissues. People with this disorder have a condition known as chronic hemolytic anemia, in which red blood cells are broken down (undergo hemolysis) prematurely, resulting in a shortage of red blood cells (anemia). Chronic hemolytic anemia can lead to unusually pale skin (pallor), yellowing of the eyes and skin (jaundice), extreme tiredness (fatigue), shortness of breath (dyspnea), and a rapid heart rate (tachycardia). An enlarged spleen (splenomegaly), an excess of iron in the blood, and small pebble-like deposits in the gallbladder or bile ducts (gallstones) may also occur in this disorder. Hemolytic anemia in GPI deficiency can range from mild to severe. In the most severe cases, affected individuals do not survive to birth. Individuals with milder disease can survive into adulthood. People with any level of severity of the disorder can have episodes of more severe hemolysis, called hemolytic crises, which can be triggered by bacterial or viral infections. A small percentage of individuals with GPI deficiency also have neurological problems, including intellectual disability and difficulty with coordinating movements (ataxia). |
frequency | How many people are affected by glucose phosphate isomerase deficiency ? | GPI deficiency is a rare cause of hemolytic anemia; its prevalence is unknown. About 50 cases have been described in the medical literature. |
genetic changes | What are the genetic changes related to glucose phosphate isomerase deficiency ? | GPI deficiency is caused by mutations in the GPI gene, which provides instructions for making an enzyme called glucose phosphate isomerase (GPI). This enzyme has two distinct functions based on its structure. When two GPI molecules form a complex (a homodimer), the enzyme plays a role in a critical energy-producing process known as glycolysis, also called the glycolytic pathway. During glycolysis, the simple sugar glucose is broken down to produce energy. Specifically, GPI is involved in the second step of the glycolytic pathway; in this step, a molecule called glucose-6-phosphate is converted to another molecule called fructose-6-phosphate. When GPI remains a single molecule (a monomer) it is involved in the development and maintenance of nerve cells (neurons). In this context, it is often known as neuroleukin (NLK). Some GPI gene mutations may result in a less stable homodimer, impairing the activity of the enzyme in the glycolytic pathway. The resulting imbalance of molecules involved in the glycolytic pathway eventually impairs the ability of red blood cells to maintain their structure, leading to hemolysis. Other GPI gene mutations may cause the monomer to break down more easily, thereby interfering with its function in nerve cells. In addition, the shortage of monomers hinders homodimer formation, which impairs the glycolytic pathway. These mutations have been identified in individuals with GPI deficiency who have both hemolytic anemia and neurological problems. |
inheritance | Is glucose phosphate isomerase deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for glucose phosphate isomerase deficiency ? | These resources address the diagnosis or management of GPI deficiency: - Genetic Testing Registry: Glucosephosphate isomerase deficiency - Genetic Testing Registry: Hemolytic anemia, nonspherocytic, due to glucose phosphate isomerase deficiency - National Heart, Lung, and Blood Institute: How is Hemolytic Anemia Diagnosed? - National Heart, Lung, and Blood Institute: How is Hemolytic Anemia Treated? These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) glucose-6-phosphate dehydrogenase deficiency ? | Glucose-6-phosphate dehydrogenase deficiency is a genetic disorder that occurs most often in males. This condition mainly affects red blood cells, which carry oxygen from the lungs to tissues throughout the body. In affected individuals, a defect in an enzyme called glucose-6-phosphate dehydrogenase causes red blood cells to break down prematurely. This destruction of red blood cells is called hemolysis. The most common medical problem associated with glucose-6-phosphate dehydrogenase deficiency is hemolytic anemia, which occurs when red blood cells are destroyed faster than the body can replace them. This type of anemia leads to paleness, yellowing of the skin and whites of the eyes (jaundice), dark urine, fatigue, shortness of breath, and a rapid heart rate. In people with glucose-6-dehydrogenase deficiency, hemolytic anemia is most often triggered by bacterial or viral infections or by certain drugs (such as some antibiotics and medications used to treat malaria). Hemolytic anemia can also occur after eating fava beans or inhaling pollen from fava plants (a reaction called favism). Glucose-6-dehydrogenase deficiency is also a significant cause of mild to severe jaundice in newborns. Many people with this disorder, however, never experience any signs or symptoms. |
frequency | How many people are affected by glucose-6-phosphate dehydrogenase deficiency ? | An estimated 400 million people worldwide have glucose-6-phosphate dehydrogenase deficiency. This condition occurs most frequently in certain parts of Africa, Asia, and the Mediterranean. It affects about 1 in 10 African American males in the United States. |
genetic changes | What are the genetic changes related to glucose-6-phosphate dehydrogenase deficiency ? | Mutations in the G6PD gene cause glucose-6-phosphate dehydrogenase deficiency. The G6PD gene provides instructions for making an enzyme called glucose-6-phosphate dehydrogenase. This enzyme is involved in the normal processing of carbohydrates. It also protects red blood cells from the effects of potentially harmful molecules called reactive oxygen species. Reactive oxygen species are byproducts of normal cellular functions. Chemical reactions involving glucose-6-phosphate dehydrogenase produce compounds that prevent reactive oxygen species from building up to toxic levels within red blood cells. If mutations in the G6PD gene reduce the amount of glucose-6-phosphate dehydrogenase or alter its structure, this enzyme can no longer play its protective role. As a result, reactive oxygen species can accumulate and damage red blood cells. Factors such as infections, certain drugs, or ingesting fava beans can increase the levels of reactive oxygen species, causing red blood cells to be destroyed faster than the body can replace them. A reduction in the amount of red blood cells causes the signs and symptoms of hemolytic anemia. Researchers believe that carriers of a G6PD mutation may be partially protected against malaria, an infectious disease carried by a certain type of mosquito. A reduction in the amount of functional glucose-6-dehydrogenase appears to make it more difficult for this parasite to invade red blood cells. Glucose-6-phosphate dehydrogenase deficiency occurs most frequently in areas of the world where malaria is common. |
inheritance | Is glucose-6-phosphate dehydrogenase deficiency inherited ? | This condition is inherited in an X-linked recessive pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. |
treatment | What are the treatments for glucose-6-phosphate dehydrogenase deficiency ? | These resources address the diagnosis or management of glucose-6-phosphate dehydrogenase deficiency: - Baby's First Test - Genetic Testing Registry: Glucose 6 phosphate dehydrogenase deficiency - MedlinePlus Encyclopedia: Glucose-6-phosphate dehydrogenase deficiency - MedlinePlus Encyclopedia: Glucose-6-phosphate dehydrogenase test - MedlinePlus Encyclopedia: Hemolytic anemia - MedlinePlus Encyclopedia: Newborn jaundice These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) North American Indian childhood cirrhosis ? | North American Indian childhood cirrhosis is a rare liver disorder that occurs in children. The liver malfunction causes yellowing of the skin and whites of the eyes (jaundice) in affected infants. The disorder worsens with age, progressively damaging the liver and leading to chronic, irreversible liver disease (cirrhosis) in childhood or adolescence. Unless it is treated with liver transplantation, North American Indian childhood cirrhosis typically causes life-threatening complications including liver failure. |
frequency | How many people are affected by North American Indian childhood cirrhosis ? | North American Indian childhood cirrhosis has been found only in children of Ojibway-Cree descent in the Abitibi region of northwestern Quebec, Canada. At least 30 affected individuals from this population have been reported. |
genetic changes | What are the genetic changes related to North American Indian childhood cirrhosis ? | North American Indian childhood cirrhosis results from at least one known mutation in the UTP4 gene. This gene provides instructions for making a protein called cirhin, whose precise function is unknown. Within cells, cirhin is located in a structure called the nucleolus, which is a small region inside the nucleus where ribosomal RNA (rRNA) is produced. A chemical cousin of DNA, rRNA is a molecule that helps assemble protein building blocks (amino acids) into functioning proteins. Researchers believe that cirhin may play a role in processing rRNA. Studies also suggest that cirhin may function by interacting with other proteins. Cirhin is found in many different types of cells, so it is unclear why the effects of North American Indian childhood cirrhosis appear to be limited to the liver. Researchers are working to determine how a UTP4 gene mutation causes the progressive liver damage characteristic of this disorder. |
inheritance | Is North American Indian childhood cirrhosis inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for North American Indian childhood cirrhosis ? | These resources address the diagnosis or management of North American Indian childhood cirrhosis: - Children's Organ Transplant Association - Genetic Testing Registry: North american indian childhood cirrhosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) factor XIII deficiency ? | Factor XIII deficiency is a rare bleeding disorder. Researchers have identified an inherited form and a less severe form that is acquired during a person's lifetime. Signs and symptoms of inherited factor XIII deficiency begin soon after birth, usually with abnormal bleeding from the umbilical cord stump. If the condition is not treated, affected individuals may have episodes of excessive and prolonged bleeding that can be life-threatening. Abnormal bleeding can occur after surgery or minor trauma. The condition can also cause spontaneous bleeding into the joints or muscles, leading to pain and disability. Women with inherited factor XIII deficiency tend to have heavy or prolonged menstrual bleeding (menorrhagia) and may experience recurrent pregnancy losses (miscarriages). Other signs and symptoms of inherited factor XIII deficiency include nosebleeds, bleeding of the gums, easy bruising, problems with wound healing, and abnormal scar formation. Inherited factor XIII deficiency also increases the risk of spontaneous bleeding inside the skull (intracranial hemorrhage), which is the leading cause of death in people with this condition. Acquired factor XIII deficiency becomes apparent later in life. People with the acquired form are less likely to have severe or life-threatening episodes of abnormal bleeding than those with the inherited form. |
frequency | How many people are affected by factor XIII deficiency ? | Inherited factor XIII deficiency affects 1 to 3 per million people worldwide. Researchers suspect that mild factor XIII deficiency, including the acquired form of the disorder, is underdiagnosed because many affected people never have a major episode of abnormal bleeding that would lead to a diagnosis. |
genetic changes | What are the genetic changes related to factor XIII deficiency ? | Inherited factor XIII deficiency results from mutations in the F13A1 gene or, less commonly, the F13B gene. These genes provide instructions for making the two parts (subunits) of a protein called factor XIII. This protein plays a critical role in the coagulation cascade, which is a series of chemical reactions that forms blood clots in response to injury. After an injury, clots seal off blood vessels to stop bleeding and trigger blood vessel repair. Factor XIII acts at the end of the cascade to strengthen and stabilize newly formed clots, preventing further blood loss. Mutations in the F13A1 or F13B gene significantly reduce the amount of functional factor XIII available to participate in blood clotting. In most people with the inherited form of the condition, factor XIII levels in the bloodstream are less than 5 percent of normal. A loss of this protein's activity weakens blood clots, preventing the clots from stopping blood loss effectively. The acquired form of factor XIII deficiency results when the production of factor XIII is reduced or when the body uses factor XIII faster than cells can replace it. Acquired factor XIII deficiency is generally mild because levels of factor XIII in the bloodstream are 20 to 70 percent of normal; levels above 10 percent of normal are usually adequate to prevent spontaneous bleeding episodes. Acquired factor XIII deficiency can be caused by disorders including an inflammatory disease of the liver called hepatitis, scarring of the liver (cirrhosis), inflammatory bowel disease, overwhelming bacterial infections (sepsis), and several types of cancer. Acquired factor XIII deficiency can also be caused by abnormal activation of the immune system, which produces specialized proteins called autoantibodies that attack and disable the factor XIII protein. The production of autoantibodies against factor XIII is sometimes associated with immune system diseases such as systemic lupus erythematosus and rheumatoid arthritis. In other cases, the trigger for autoantibody production is unknown. |
inheritance | Is factor XIII deficiency inherited ? | Inherited factor XIII deficiency is considered to have an autosomal recessive pattern of inheritance, which means that it results when both copies of either the F13A1 gene or the F13B gene in each cell have mutations. Some people, including parents of individuals with factor XIII deficiency, carry a single mutated copy of the F13A1 or F13B gene in each cell. These mutation carriers have a reduced amount of factor XIII in their bloodstream (20 to 60 percent of normal), and they may experience abnormal bleeding after surgery, dental work, or major trauma. However, most people who carry one mutated copy of the F13A1 or F13B gene do not have abnormal bleeding episodes under normal circumstances, and so they never come to medical attention. The acquired form of factor XIII deficiency is not inherited and does not run in families. |
treatment | What are the treatments for factor XIII deficiency ? | These resources address the diagnosis or management of factor XIII deficiency: - Genetic Testing Registry: Factor xiii, a subunit, deficiency of - Genetic Testing Registry: Factor xiii, b subunit, deficiency of These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) cryptogenic cirrhosis ? | Cryptogenic cirrhosis is a condition that impairs liver function. People with this condition develop irreversible liver disease caused by scarring of the liver (cirrhosis), typically in mid- to late adulthood. The liver is a part of the digestive system that helps break down food, store energy, and remove waste products, including toxins. Minor damage to the liver can be repaired by the body. However, severe or long-term damage can lead to the replacement of normal liver tissue with scar tissue. In the early stages of cryptogenic cirrhosis, people often have no symptoms because the liver has enough normal tissue to function. Signs and symptoms become apparent as more of the liver is replaced by scar tissue. Affected individuals can experience fatigue, weakness, loss of appetite, weight loss, nausea, swelling (edema), enlarged blood vessels, and yellowing of the skin and whites of the eyes (jaundice). People with cryptogenic cirrhosis may develop high blood pressure in the vein that supplies blood to the liver (portal hypertension). Cryptogenic cirrhosis can lead to type 2 diabetes, although the mechanism is unclear. Some people with cryptogenic cirrhosis develop cancer of the liver (hepatocellular cancer). |
frequency | How many people are affected by cryptogenic cirrhosis ? | Cirrhosis affects more than 600,000 people in the United States; cryptogenic cirrhosis likely accounts for 5 to 30 percent of these cases. |
genetic changes | What are the genetic changes related to cryptogenic cirrhosis ? | Unlike most cases of cirrhosis, cryptogenic cirrhosis is not caused by the hepatitis C or B virus or chronic alcohol use. A diagnosis of cryptogenic cirrhosis is typically given when all other causes of cirrhosis have been ruled out. When a disorder occurs without an apparent underlying reason, it is described as cryptogenic. Research has shown that many cases of cryptogenic cirrhosis likely result from a condition called non-alcoholic fatty liver disease (NAFLD). In NAFLD, fat accumulates in the liver, impairing its function. If the fat buildup leads to inflammation and damage to liver tissue, NAFLD progresses to a condition called non-alcoholic steatohepatitis (NASH). Long term inflammation in people with NASH can cause the formation of scar tissue and a decrease in fat buildup. As a result, individuals progress from NASH to cirrhosis. Cryptogenic cirrhosis may also develop from autoimmune hepatitis, which is a condition that occurs when the body's immune system malfunctions and attacks the liver, causing inflammation and liver damage. In very rare cases, cryptogenic cirrhosis has been associated with mutations in genes that provide instructions for making certain keratin proteins. Keratins are a group of tough, fibrous proteins that form the structural framework of certain cells, particularly cells that make up the skin, hair, nails, and similar tissues. People with these keratin gene mutations are more likely to have fibrous deposits in their livers than individuals without the mutations. These deposits impair liver function, leading to cirrhosis. Mutations in these genes have also been found in people with other liver disorders. In many cases, the cause of cryptogenic cirrhosis is unknown. Many people with predisposing conditions do not develop cirrhosis. Researchers are working to discover the causes of cryptogenic cirrhosis as well as to find out why some people seem to be protected from developing cirrhosis and others seem to be susceptible. |
inheritance | Is cryptogenic cirrhosis inherited ? | Most cases of cryptogenic cirrhosis are not inherited. However, people with a family history of liver disease or autoimmune disease are at an increased risk of developing these diseases themselves, and possibly cirrhosis. In individuals with an associated keratin gene mutation, the risk of developing cryptogenic cirrhosis appears to have an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means that one copy of an altered gene in each cell is sufficient to increase the risk of developing cryptogenic cirrhosis. In these families, people inherit an increased risk of cryptogenic cirrhosis, not the disease itself. |
treatment | What are the treatments for cryptogenic cirrhosis ? | These resources address the diagnosis or management of cryptogenic cirrhosis: - Children's Hospital of Pittsburgh: Cirrhosis - Cleveland Clinic: Cirrhosis of the Liver - Genetic Testing Registry: Cirrhosis, cryptogenic - Genetic Testing Registry: Familial cirrhosis - MedlinePlus Encyclopedia: Cirrhosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) medullary cystic kidney disease type 1 ? | Medullary cystic kidney disease type 1 (MCKD1) is an inherited condition that affects the kidneys. It leads to scarring (fibrosis) and impaired function of the kidneys, usually beginning in adulthood. The kidneys filter fluid and waste products from the body. They also reabsorb needed nutrients and release them back into the blood. As MCKD1 progresses, the kidneys are less able to function, resulting in kidney failure. Declining kidney function in people with MCKD1 leads to the signs and symptoms of the condition. The features are variable, even among members of the same family. Many individuals with MCKD1 develop high blood pressure (hypertension), especially as kidney function worsens. Some develop high levels of a waste product called uric acid in the blood (hyperuricemia) because the damaged kidneys are unable to remove uric acid effectively. In a small number of affected individuals, the buildup of this waste product can cause gout, which is a form of arthritis resulting from uric acid crystals in the joints. Although the condition is named medullary cystic kidney disease, only about 40 percent of affected individuals have medullary cysts, which are fluid filled pockets found in a particular region of the kidney. When present, the cysts are usually found in the inner part of the kidney (the medullary region) or the border between the inner and outer parts (corticomedullary region). These cysts are visible by tests such as ultrasound or CT scan. |
frequency | How many people are affected by medullary cystic kidney disease type 1 ? | MCKD1 is a rare disorder, although its prevalence is unknown. |
genetic changes | What are the genetic changes related to medullary cystic kidney disease type 1 ? | MCKD1 is caused by mutations in the MUC1 gene. This gene provides instructions for making a protein called mucin 1, which is one of several mucin proteins that make up mucus. Mucus is a slippery substance that lubricates the lining of the airways, digestive system, reproductive system, and other organs and tissues and protects them from foreign invaders and other particles. In addition to its role in mucus, mucin 1 relays signals from outside the cell to the cell's nucleus. Through this cellular signaling, mucin 1 is thought to be involved in the growth, movement, and survival of cells. Research suggests that mucin 1 plays a role in the normal development of the kidneys. MCKD1 is caused by the insertion of a single DNA building block (nucleotide) called cytosine into the MUC1 gene. These mutations have been found in one particular region of the gene. They lead to the production of an altered protein. It is unclear how this change causes kidney disease. |
inheritance | Is medullary cystic kidney disease type 1 inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. |
treatment | What are the treatments for medullary cystic kidney disease type 1 ? | These resources address the diagnosis or management of medullary cystic kidney disease type 1: - MedlinePlus Encyclopedia: Medullary Cystic Kidney Disease - Merck Manual for Health Care Professionals: Nephronophthisis and Medullary Cystic Kidney Disease Complex These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Gilbert syndrome ? | Gilbert syndrome is a relatively mild condition characterized by periods of elevated levels of a toxic substance called bilirubin in the blood (hyperbilirubinemia). Bilirubin, which has an orange-yellow tint, is produced when red blood cells are broken down. This substance is removed from the body only after it undergoes a chemical reaction in the liver, which converts the toxic form of bilirubin (unconjugated bilirubin) to a nontoxic form called conjugated bilirubin. People with Gilbert syndrome have a buildup of unconjugated bilirubin in their blood (unconjugated hyperbilirubinemia). In affected individuals, bilirubin levels fluctuate and very rarely increase to levels that cause jaundice, which is yellowing of the skin and whites of the eyes. Gilbert syndrome is usually recognized in adolescence. If people with this condition have episodes of hyperbilirubinemia, these episodes are generally mild and typically occur when the body is under stress, for instance because of dehydration, prolonged periods without food (fasting), illness, vigorous exercise, or menstruation. Some people with Gilbert syndrome also experience abdominal discomfort or tiredness. However, approximately 30 percent of people with Gilbert syndrome have no signs or symptoms of the condition and are discovered only when routine blood tests reveal elevated unconjugated bilirubin levels. |
frequency | How many people are affected by Gilbert syndrome ? | Gilbert syndrome is a common condition that is estimated to affect 3 to 7 percent of Americans. |
genetic changes | What are the genetic changes related to Gilbert syndrome ? | Changes in the UGT1A1 gene cause Gilbert syndrome. This gene provides instructions for making the bilirubin uridine diphosphate glucuronosyltransferase (bilirubin-UGT) enzyme, which is found primarily in liver cells and is necessary for the removal of bilirubin from the body. The bilirubin-UGT enzyme performs a chemical reaction called glucuronidation. During this reaction, the enzyme transfers a compound called glucuronic acid to unconjugated bilirubin, converting it to conjugated bilirubin. Glucuronidation makes bilirubin dissolvable in water so that it can be removed from the body. Gilbert syndrome occurs worldwide, but some mutations occur more often in particular populations. In many populations, the most common genetic change that causes Gilbert syndrome (known as UGT1A1*28) occurs in an area near the UGT1A1 gene called the promoter region, which controls the production of the bilirubin-UGT enzyme. This genetic change impairs enzyme production. However, this change is uncommon in Asian populations, and affected Asians often have a mutation that changes a single protein building block (amino acid) in the bilirubin-UGT enzyme. This type of mutation, known as a missense mutation, results in reduced enzyme function. People with Gilbert syndrome have approximately 30 percent of normal bilirubin-UGT enzyme function. As a result, unconjugated bilirubin is not glucuronidated quickly enough. This toxic substance then builds up in the body, causing mild hyperbilirubinemia. Not everyone with the genetic changes that cause Gilbert syndrome develops hyperbilirubinemia, indicating that additional factors, such as conditions that further hinder the glucuronidation process, may be necessary for development of the condition. For example, red blood cells may break down too easily, releasing excess amounts of bilirubin that the impaired enzyme cannot keep up with. Alternatively, movement of bilirubin into the liver, where it would be glucuronidated, may be impaired. These other factors may be due to changes in other genes. |
inheritance | Is Gilbert syndrome inherited ? | Gilbert syndrome can have different inheritance patterns. When the condition is caused by the UGT1A1*28 change in the promoter region of the UGT1A1 gene, it is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have the mutation. 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. When the condition is caused by a missense mutation in the UGT1A1 gene, it is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. A more severe condition known as Crigler-Najjar syndrome occurs when both copies of the UGT1A1 gene have mutations. |
treatment | What are the treatments for Gilbert syndrome ? | These resources address the diagnosis or management of Gilbert syndrome: - Genetic Testing Registry: Gilbert's syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) glycogen storage disease type IX ? | Glycogen storage disease type IX (also known as GSD IX) is a condition caused by the inability to break down a complex sugar called glycogen. The different forms of the condition can affect glycogen breakdown in liver cells or muscle cells or sometimes both. A lack of glycogen breakdown interferes with the normal function of the affected tissue. When GSD IX affects the liver, the signs and symptoms typically begin in early childhood. The initial features are usually an enlarged liver (hepatomegaly) and slow growth. Affected children are often shorter than normal. During prolonged periods without food (fasting), affected individuals may have low blood sugar (hypoglycemia) or elevated levels of ketones in the blood (ketosis). Ketones are molecules produced during the breakdown of fats, which occurs when stored sugars are unavailable. Affected children may have delayed development of motor skills, such as sitting, standing, or walking, and some have mild muscle weakness. Puberty is delayed in some adolescents with GSD IX. In the form of the condition that affects the liver, the signs and symptoms usually improve with age. Typically, individuals catch up developmentally, and adults reach normal height. However, some affected individuals have a buildup of scar tissue (fibrosis) in the liver, which can rarely progress to irreversible liver disease (cirrhosis). GSD IX can affect muscle tissue, although this form of the condition is very rare and not well understood. The features of this form of the condition can appear anytime from childhood to adulthood. Affected individuals may experience fatigue, muscle pain, and cramps, especially during exercise (exercise intolerance). Most affected individuals have muscle weakness that worsens over time. GSD IX can cause myoglobinuria, which occurs when muscle tissue breaks down abnormally and releases a protein called myoglobin that is excreted in the urine. Myoglobinuria can cause the urine to be red or brown. In a small number of people with GSD IX, the liver and muscles are both affected. These individuals develop a combination of the features described above, although the muscle problems are usually mild. |
frequency | How many people are affected by glycogen storage disease type IX ? | GSD IX that affects the liver is estimated to occur in 1 in 100,000 people. The forms of the disease that affect muscles or both muscles and liver are much less common, although the prevalence is unknown. |
genetic changes | What are the genetic changes related to glycogen storage disease type IX ? | Mutations in the PHKA1, PHKA2, PHKB, or PHKG2 genes are known to cause GSD IX. These genes provide instructions for making pieces (subunits) of an enzyme called phosphorylase b kinase. The enzyme is made up of 16 subunits, four each of the alpha, beta, gamma, and delta subunits. At least two different versions of phosphorylase b kinase are formed from the subunits: one is most abundant in liver cells and the other in muscle cells. The PHKA1 and PHKA2 genes provide instructions for making alpha subunits of phosphorylase b kinase. The protein produced from the PHKA1 gene is a subunit of the muscle enzyme, while the protein produced from the PHKA2 gene is part of the liver enzyme. The PHKB gene provides instructions for making the beta subunit, which is found in both the muscle and the liver. The PHKG2 gene provides instructions for making the gamma subunit of the liver enzyme. Whether in the liver or the muscles, phosphorylase b kinase plays an important role in providing energy for cells. The main source of cellular energy is a simple sugar called glucose. Glucose is stored in muscle and liver cells in a form called glycogen. Glycogen can be broken down rapidly when glucose is needed, for instance to maintain normal levels of glucose in the blood between meals or for energy during exercise. Phosphorylase b kinase turns on (activates) the enzyme that breaks down glycogen. Although the effects of gene mutations on the respective protein subunits are unknown, mutations in the PHKA1, PHKA2, PHKB, and PHKG2 genes reduce the activity of phosphorylase b kinase in liver or muscle cells and in blood cells. Reduction of this enzyme's function impairs glycogen breakdown. As a result, glycogen accumulates in and damages cells, and glucose is not available for energy. Glycogen accumulation in the liver leads to hepatomegaly, and the liver's inability to break down glycogen for glucose contributes to hypoglycemia and ketosis. Reduced energy production in muscle cells leads to muscle weakness, pain, and cramping. |
inheritance | Is glycogen storage disease type IX inherited ? | GSD IX can have different inheritance patterns depending on the genetic cause of the condition. When caused by mutations in the PHKA1 or PHKA2 gene, GSD IX is inherited in an X-linked recessive pattern. These genes 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 the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. However, some women with one altered copy of the PHKA2 gene have signs and symptoms of GSD IX, such as mild hepatomegaly or short stature in childhood. These features are usually mild but can be more severe in rare cases. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. When the condition is caused by mutations in the PHKB or PHKG2 gene, it is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for glycogen storage disease type IX ? | These resources address the diagnosis or management of glycogen storage disease type IX: - Gene Review: Gene Review: Phosphorylase Kinase Deficiency - Genetic Testing Registry: Glycogen storage disease IXb - Genetic Testing Registry: Glycogen storage disease IXc - Genetic Testing Registry: Glycogen storage disease IXd - Genetic Testing Registry: Glycogen storage disease type IXa1 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) nonsyndromic holoprosencephaly ? | Nonsyndromic holoprosencephaly is an abnormality of brain development that also affects the head and face. Normally, the brain divides into two halves (hemispheres) during early development. Holoprosencephaly occurs when the brain fails to divide properly into the right and left hemispheres. This condition is called nonsyndromic to distinguish it from other types of holoprosencephaly caused by genetic syndromes, chromosome abnormalities, or substances that cause birth defects (teratogens). The severity of nonsyndromic holoprosencephaly varies widely among affected individuals, even within the same family. Nonsyndromic holoprosencephaly can be grouped into four types according to the degree of brain division. From most to least severe, the types are known as alobar, semi-lobar, lobar, and middle interhemispheric variant (MIHV). In the most severe forms of nonsyndromic holoprosencephaly, the brain does not divide at all. These affected individuals have one central eye (cyclopia) and a tubular nasal structure (proboscis) located above the eye. Most babies with severe nonsyndromic holoprosencephaly die before birth or soon after. In the less severe forms, the brain is partially divided and the eyes are usually set close together (hypotelorism). The life expectancy of these affected individuals varies depending on the severity of symptoms. People with nonsyndromic holoprosencephaly often have a small head (microcephaly), although they can develop a buildup of fluid in the brain (hydrocephalus) that causes increased head size (macrocephaly). Other features may include an opening in the roof of the mouth (cleft palate) with or without a split in the upper lip (cleft lip), one central front tooth instead of two (a single maxillary central incisor), and a flat nasal bridge. The eyeballs may be abnormally small (microphthalmia) or absent (anophthalmia). Some individuals with nonsyndromic holoprosencephaly have a distinctive pattern of facial features, including a narrowing of the head at the temples, outside corners of the eyes that point upward (upslanting palpebral fissures), large ears, a short nose with upturned nostrils, and a broad and deep space between the nose and mouth (philtrum). In general, the severity of facial features is directly related to the severity of the brain abnormalities. However, individuals with mildly affected facial features can have severe brain abnormalities. Some people do not have apparent structural brain abnormalities but have some of the facial features associated with this condition. These individuals are considered to have a form of the disorder known as microform holoprosencephaly and are typically identified after the birth of a severely affected family member. Most people with nonsyndromic holoprosencephaly have developmental delay and intellectual disability. Affected individuals also frequently have a malfunctioning pituitary gland, which is a gland located at the base of the brain that produces several hormones. Because pituitary dysfunction leads to the partial or complete absence of these hormones, it can cause a variety of disorders. Most commonly, people with nonsyndromic holoprosencephaly and pituitary dysfunction develop diabetes insipidus, a condition that disrupts the balance between fluid intake and urine excretion. Dysfunction in other parts of the brain can cause seizures, feeding difficulties, and problems regulating body temperature, heart rate, and breathing. The sense of smell may be diminished (hyposmia) or completely absent (anosmia) if the part of the brain that processes smells is underdeveloped or missing. |
frequency | How many people are affected by nonsyndromic holoprosencephaly ? | Nonsyndromic holoprosencephaly accounts for approximately 25 to 50 percent of all cases of holoprosencephaly, which affects an estimated 1 in 10,000 newborns. |
genetic changes | What are the genetic changes related to nonsyndromic holoprosencephaly ? | Mutations in 11 genes have been found to cause nonsyndromic holoprosencephaly. These genes provide instructions for making proteins that are important for normal embryonic development, particularly for determining the shape of the brain and face. About 25 percent of people with nonsyndromic holoprosencephaly have a mutation in one of these four genes: SHH, ZIC2, SIX3, or TGIF1. Mutations in the other genes related to nonsyndromic holoprosencephaly are found in only a small percentage of cases. Many individuals with this condition do not have an identified gene mutation. The cause of the disorder is unknown in these individuals. The brain normally divides into right and left hemispheres during the third to fourth week of pregnancy. To establish the line that separates the two hemispheres (the midline), the activity of many genes must be tightly regulated and coordinated. These genes provide instructions for making signaling proteins, which instruct the cells within the brain to form the right and left hemispheres. Signaling proteins are also important for the formation of the eyes. During early development, the cells that develop into the eyes form a single structure called the eye field. This structure is located in the center of the developing face. The signaling protein produced from the SHH gene causes the eye field to separate into two distinct eyes. The SIX3 gene is involved in the formation of the lens of the eye and the specialized tissue at the back of the eye that detects light and color (the retina). Mutations in the genes that cause nonsyndromic holoprosencephaly lead to the production of abnormal or nonfunctional signaling proteins. Without the correct signals, the eyes will not form normally and the brain does not separate into two hemispheres. The development of other parts of the face is affected if the eyes do not move to their proper position. The signs and symptoms of nonsyndromic holoprosencephaly are caused by abnormal development of the brain and face. Researchers believe that other genetic or environmental factors, many of which have not been identified, play a role in determining the severity of nonsyndromic holoprosencephaly. |
inheritance | Is nonsyndromic holoprosencephaly inherited ? | Nonsyndromic holoprosencephaly is inherited in an autosomal dominant pattern, which means an alteration in one copy of a gene in each cell is usually sufficient to cause the disorder. However, not all people with a gene mutation will develop signs and symptoms of the condition. In some cases, an affected person inherits the mutation from one parent who may or may not have mild features of the condition. Other cases result from a new gene mutation and occur in people with no history of the disorder in their family. |
treatment | What are the treatments for nonsyndromic holoprosencephaly ? | These resources address the diagnosis or management of nonsyndromic holoprosencephaly: - Gene Review: Gene Review: Holoprosencephaly Overview - Genetic Testing Registry: Holoprosencephaly 1 - Genetic Testing Registry: Holoprosencephaly 10 - Genetic Testing Registry: Holoprosencephaly 2 - Genetic Testing Registry: Holoprosencephaly 3 - Genetic Testing Registry: Holoprosencephaly 4 - Genetic Testing Registry: Holoprosencephaly 5 - Genetic Testing Registry: Holoprosencephaly 6 - Genetic Testing Registry: Holoprosencephaly 7 - Genetic Testing Registry: Holoprosencephaly 8 - Genetic Testing Registry: Holoprosencephaly 9 - Genetic Testing Registry: Holoprosencephaly sequence - Genetic Testing Registry: NODAL-Related Holoprosencephaly These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) succinic semialdehyde dehydrogenase deficiency ? | Succinic semialdehyde dehydrogenase deficiency is a disorder that can cause a variety of neurological problems. People with this condition typically have developmental delay, especially involving speech development; intellectual disability; and decreased muscle tone (hypotonia) soon after birth. About half of those affected experience seizures, difficulty coordinating movements (ataxia), decreased reflexes (hyporeflexia), and behavioral problems. The most common behavioral problems associated with this condition are sleep disturbances, hyperactivity, difficulty maintaining attention, and anxiety. Less frequently, affected individuals may have increased aggression, hallucinations, obsessive-compulsive disorder (OCD), and self-injurious behavior, including biting and head banging. People with this condition can also have problems controlling eye movements. Less common features of succinic semialdehyde dehydrogenase deficiency include uncontrollable movements of the limbs (choreoathetosis), involuntary tensing of the muscles (dystonia), muscle twitches (myoclonus), and a progressive worsening of ataxia. |
frequency | How many people are affected by succinic semialdehyde dehydrogenase deficiency ? | Approximately 350 people with succinic semialdehyde dehydrogenase deficiency have been reported worldwide. |
genetic changes | What are the genetic changes related to succinic semialdehyde dehydrogenase deficiency ? | Mutations in the ALDH5A1 gene cause succinic semialdehyde dehydrogenase deficiency. The ALDH5A1 gene provides instructions for producing the succinic semialdehyde dehydrogenase enzyme. This enzyme is involved in the breakdown of a chemical that transmits signals in the brain (neurotransmitter) called gamma-amino butyric acid (GABA). The primary role of GABA is to prevent the brain from being overloaded with too many signals. A shortage (deficiency) of succinic semialdehyde dehydrogenase leads to an increase in the amount of GABA and a related molecule called gamma-hydroxybutyrate (GHB) in the body, particularly the brain and spinal cord (central nervous system). It is unclear how an increase in GABA and GHB causes developmental delay, seizures, and other signs and symptoms of succinic semialdehyde dehydrogenase deficiency. |
inheritance | Is succinic semialdehyde dehydrogenase deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for succinic semialdehyde dehydrogenase deficiency ? | These resources address the diagnosis or management of succinic semialdehyde dehydrogenase deficiency: - Gene Review: Gene Review: Succinic Semialdehyde Dehydrogenase Deficiency - Genetic Testing Registry: Succinate-semialdehyde dehydrogenase deficiency - MedlinePlus Encyclopedia: Hyperactivity These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) familial erythrocytosis ? | Familial erythrocytosis is an inherited condition characterized by an increased number of red blood cells (erythrocytes). The primary function of these cells is to carry oxygen from the lungs to tissues and organs throughout the body. Signs and symptoms of familial erythrocytosis can include headaches, dizziness, nosebleeds, and shortness of breath. The excess red blood cells also increase the risk of developing abnormal blood clots that can block the flow of blood through arteries and veins. If these clots restrict blood flow to essential organs and tissues (particularly the heart, lungs, or brain), they can cause life-threatening complications such as a heart attack or stroke. However, many people with familial erythrocytosis experience only mild signs and symptoms or never have any problems related to their extra red blood cells. |
frequency | How many people are affected by familial erythrocytosis ? | Familial erythrocytosis is a rare condition; its prevalence is unknown. |
genetic changes | What are the genetic changes related to familial erythrocytosis ? | Familial erythrocytosis can result from mutations in the EPOR, VHL, EGLN1, or EPAS1 gene. Researchers define four types of familial erythrocytosis, ECYT1 through ECYT4, based on which of these genes is altered. The EPOR gene provides instructions for making a protein known as the erythropoietin receptor, which is found on the surface of certain blood-forming cells in the bone marrow. Erythropoietin is a hormone that directs the production of new red blood cells. Erythropoietin fits into the receptor like a key into a lock, triggering signaling pathways that lead to the formation of red blood cells. Mutations in the EPOR gene cause the erythropoietin receptor to be turned on for an abnormally long time after attaching to erythropoietin. The overactive receptor signals the production of red blood cells even when they are not needed, which results in an excess of these cells in the bloodstream. When familial erythrocytosis is caused by mutations in the EPOR gene, it is known as ECYT1. The proteins produced from the VHL, EGLN1, and EPAS1 genes are also involved in red blood cell production; they each play a role in regulating erythropoietin. The protein produced from the EPAS1 gene is one component of a protein complex called hypoxia-inducible factor (HIF). When oxygen levels are lower than normal (hypoxia), HIF activates genes that help the body adapt, including the gene that provides instructions for making erythropoietin. Erythropoietin stimulates the production of more red blood cells to carry oxygen to organs and tissues. The proteins produced from the VHL and EGLN1 genes indirectly regulate erythropoietin by controlling the amount of available HIF. Mutations in any of these three genes can disrupt the regulation of red blood cell formation, leading to an overproduction of these cells. When familial erythrocytosis results from VHL gene mutations it is known as ECYT2; when the condition is caused by EGLN1 gene mutations it is called ECYT3; and when the condition results from EPAS1 gene mutations it is known as ECYT4. Researchers have also described non-familial (acquired) forms of erythrocytosis. Causes of acquired erythrocytosis include long-term exposure to high altitude, chronic lung or heart disease, episodes in which breathing slows or stops for short periods during sleep (sleep apnea), and certain types of tumors. Another form of acquired erythrocytosis, called polycythemia vera, results from somatic (non-inherited) mutations in other genes involved in red blood cell production. In some cases, the cause of erythrocytosis is unknown. |
inheritance | Is familial erythrocytosis inherited ? | Familial erythrocytosis can have different inheritance patterns depending on the gene involved. When the condition is caused by mutations in the EPOR, EGLN1, or EPAS1 gene, it has 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. Most affected individuals inherit the altered gene from one affected parent. When familial erythrocytosis is caused by mutations in the VHL 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. |
treatment | What are the treatments for familial erythrocytosis ? | These resources address the diagnosis or management of familial erythrocytosis: - Genetic Testing Registry: Erythrocytosis, familial, 2 - Genetic Testing Registry: Erythrocytosis, familial, 3 - Genetic Testing Registry: Erythrocytosis, familial, 4 - Genetic Testing Registry: Familial erythrocytosis, 1 - MedlinePlus Encyclopedia: Erythropoietin Test These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) autosomal dominant congenital stationary night blindness ? | Autosomal dominant congenital stationary night blindness is a disorder of the retina, which is the specialized tissue at the back of the eye that detects light and color. People with this condition typically have difficulty seeing and distinguishing objects in low light (night blindness). For example, they are not able to identify road signs at night and some people cannot see stars in the night sky. Affected individuals have normal daytime vision and typically do not have other vision problems related to this disorder. The night blindness associated with this condition is congenital, which means it is present from birth. This vision impairment tends to remain stable (stationary); it does not worsen over time. |
frequency | How many people are affected by autosomal dominant congenital stationary night blindness ? | Autosomal dominant congenital stationary night blindness is likely a rare disease; however, its prevalence is unknown. |
genetic changes | What are the genetic changes related to autosomal dominant congenital stationary night blindness ? | Mutations in the RHO, GNAT1, or PDE6B gene cause autosomal dominant congenital stationary night blindness. The proteins produced from these genes are necessary for normal vision, particularly in low-light conditions. These proteins are found in specialized light receptor cells in the retina called rods. Rods transmit visual signals from the eye to the brain when light is dim. The RHO gene provides instructions for making a protein called rhodopsin, which is turned on (activated) by light entering the eye. Rhodopsin then attaches (binds) to and activates the protein produced from the GNAT1 gene, alpha ()-transducin. The -transducin protein then triggers the activation of a protein called cGMP-PDE, which is made up of multiple parts (subunits) including a subunit produced from the PDE6B gene. Activated cGMP-PDE triggers a series of chemical reactions that create electrical signals. These signals are transmitted from rod cells to the brain, where they are interpreted as vision. Mutations in the RHO, GNAT1, or PDE6B gene disrupt the normal signaling that occurs within rod cells. As a result, the rods cannot effectively transmit signals to the brain, leading to a lack of visual perception in low light. |
inheritance | Is autosomal dominant congenital stationary night blindness inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. |
treatment | What are the treatments for autosomal dominant congenital stationary night blindness ? | These resources address the diagnosis or management of autosomal dominant congenital stationary night blindness: - Genetic Testing Registry: Congenital stationary night blindness These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Romano-Ward syndrome ? | Romano-Ward syndrome is a condition that causes a disruption of the heart's normal rhythm (arrhythmia). This disorder is a form of long QT syndrome, which is a heart condition that causes the heart (cardiac) muscle to take longer than usual to recharge between beats. The irregular heartbeats can lead to fainting (syncope) or cardiac arrest and sudden death. |
frequency | How many people are affected by Romano-Ward syndrome ? | Romano-Ward syndrome is the most common form of inherited long QT syndrome, affecting an estimated 1 in 7,000 people worldwide. The disorder may actually be more common than this estimate, however, because some people never experience any symptoms associated with arrhythmia and therefore may not have been diagnosed. |
genetic changes | What are the genetic changes related to Romano-Ward syndrome ? | Mutations in the KCNE1, KCNE2, KCNH2, KCNQ1, and SCN5A genes cause Romano-Ward syndrome. These genes provide instructions for making proteins that act as channels across the cell membrane. These channels transport positively charged atoms (ions), such as potassium and sodium, into and out of cells. In cardiac muscle, ion channels play critical roles in maintaining the heart's normal rhythm. Mutations in any of these genes alter the structure or function of these channels, which changes the flow of ions between cells. A disruption in ion transport alters the way the heart beats, leading to the abnormal heart rhythm characteristic of Romano-Ward syndrome. Unlike most genes related to Romano-Ward syndrome, the ANK2 gene does not provide instructions for making an ion channel. The ANK2 protein, ankyrin-2, ensures that certain other proteins (particularly ion channels) are inserted into the cell membrane appropriately. A mutation in the ANK2 gene likely alters the flow of ions between cells in the heart, which disrupts the heart's normal rhythm. ANK2 mutations can cause a variety of heart problems, including the irregular heartbeat often found in Romano-Ward syndrome. It is unclear whether mutations in the ANK2 gene cause Romano-Ward syndrome or lead to another heart condition with some of the same signs and symptoms. |
inheritance | Is Romano-Ward syndrome inherited ? | This condition is typically inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the mutation from one affected parent. A small percentage of cases result from new mutations in one of the genes described above. These cases occur in people with no history of Romano-Ward syndrome in their family. |
treatment | What are the treatments for Romano-Ward syndrome ? | These resources address the diagnosis or management of Romano-Ward syndrome: - Gene Review: Gene Review: Long QT Syndrome - Genetic Testing Registry: Long QT syndrome 1 - Genetic Testing Registry: Romano-Ward syndrome - MedlinePlus Encyclopedia: Arrhythmias These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Timothy syndrome ? | Timothy syndrome is a rare disorder that affects many parts of the body including the heart, digits (fingers and toes), and the nervous system. Timothy syndrome is characterized by a heart condition called long QT syndrome, which causes the heart (cardiac) muscle to take longer than usual to recharge between beats. This abnormality in the heart's electrical system can cause irregular heartbeats (arrhythmia), which can lead to sudden death. Many people with Timothy syndrome are also born with structural heart defects that affect the heart's ability to pump blood effectively. As a result of these serious heart problems, many people with Timothy syndrome live only into childhood. The most common cause of death is a form of arrhythmia called ventricular tachyarrhythmia, in which the lower chambers of the heart (the ventricles) beat abnormally fast and lead to cardiac arrest. Timothy syndrome is also characterized by webbing or fusion of the skin between some fingers or toes (cutaneous syndactyly). About half of affected people have distinctive facial features such as a flattened nasal bridge, low-set ears, a small upper jaw, and a thin upper lip. Children with this condition have small, misplaced teeth and frequent cavities (dental caries). Additional signs and symptoms of Timothy syndrome can include baldness at birth, frequent infections, episodes of low blood sugar (hypoglycemia), and an abnormally low body temperature (hypothermia). Researchers have found that many children with Timothy syndrome have the characteristic features of autism or similar conditions known as autistic spectrum disorders. Affected children tend to have impaired communication and socialization skills, as well as delayed development of speech and language. Other nervous system abnormalities, including intellectual disability and seizures, can also occur in children with Timothy syndrome. Researchers have identified two forms of Timothy syndrome. Type 1, which is also known as the classic type, includes all of the characteristic features described above. Type 2, or the atypical type, causes a more severe form of long QT syndrome and a greater risk of arrhythmia and sudden death. Unlike the classic type, the atypical type does not appear to cause webbing of the fingers or toes. |
frequency | How many people are affected by Timothy syndrome ? | Timothy syndrome is a rare condition; fewer than 20 people with this disorder have been reported worldwide. The classic type of Timothy syndrome appears to be more common than the atypical type, which has been identified in only two individuals. |
genetic changes | What are the genetic changes related to Timothy syndrome ? | Mutations in the CACNA1C gene are responsible for all reported cases of Timothy syndrome. This gene provides instructions for making a protein that acts as a channel across cell membranes. This channel, known as CaV1.2, is one of several channels that transport positively charged calcium atoms (calcium ions) into cells. Calcium ions are involved in many different cellular functions, including cell-to-cell communication, the tensing of muscle fibers (muscle contraction), and the regulation of certain genes. CaV1.2 calcium channels are particularly important for the normal function of heart and brain cells. In cardiac muscle, these channels play a critical role in maintaining the heart's normal rhythm. Their role in the brain and in other tissues is less clear. Mutations in the CACNA1C gene change the structure of CaV1.2 channels. The altered channels stay open much longer than usual, which allows calcium ions to continue flowing into cells abnormally. The resulting overload of calcium ions within cardiac muscle cells changes the way the heart beats and can cause arrhythmia. Researchers are working to determine how an increase in calcium ion transport in other tissues, including cells in the brain, underlies the other features of Timothy syndrome. |
inheritance | Is Timothy syndrome inherited ? | This condition is considered to have an autosomal dominant pattern of inheritance, which means one copy of the altered CACNA1C 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. Less commonly, people with Timothy syndrome inherit the altered gene from an unaffected parent who is mosaic for a CACNA1C mutation. Mosaicism means that the parent has the mutation in some cells (including egg or sperm cells), but not in others. |
treatment | What are the treatments for Timothy syndrome ? | These resources address the diagnosis or management of Timothy syndrome: - Gene Review: Gene Review: Timothy Syndrome - Genetic Testing Registry: Timothy syndrome - MedlinePlus Encyclopedia: Arrhythmias - MedlinePlus Encyclopedia: Congenital Heart Disease - MedlinePlus Encyclopedia: Webbing of the Fingers or Toes These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) phosphoglycerate kinase deficiency ? | Phosphoglycerate kinase deficiency is a genetic disorder that affects the body's ability to break down the simple sugar glucose, which is the primary energy source for most cells. Researchers have described two major forms of the condition. The most common form is sometimes called the hemolytic form. It is characterized by a condition known as chronic hemolytic anemia, in which red blood cells are broken down (undergo hemolysis) prematurely. Chronic hemolytic anemia can lead to unusually pale skin (pallor), yellowing of the eyes and skin (jaundice), fatigue, shortness of breath, and a rapid heart rate. Some people with the hemolytic form also have symptoms related to abnormal brain function, including intellectual disability, seizures, and stroke. The other form of phosphoglycerate kinase deficiency is often called the myopathic form. It primarily affects muscles, causing progressive weakness, pain, and cramping, particularly with exercise. During exercise, muscle tissue can be broken down, releasing a protein called myoglobin. This protein is processed by the kidneys and released in the urine (myoglobinuria). If untreated, myoglobinuria can lead to kidney failure. Most people with phosphoglycerate kinase deficiency have either the hemolytic form or the myopathic form. However, other combinations of signs and symptoms (such as muscle weakness with neurologic symptoms) have also been reported. |
frequency | How many people are affected by phosphoglycerate kinase deficiency ? | Phosphoglycerate kinase deficiency appears to be a rare disorder. About 30 families with affected members have been reported in the scientific literature. |
genetic changes | What are the genetic changes related to phosphoglycerate kinase deficiency ? | Phosphoglycerate kinase deficiency is caused by mutations in the PGK1 gene. This gene provides instructions for making an enzyme called phosphoglycerate kinase, which is involved in a critical energy-producing process in cells known as glycolysis. During glycolysis, the simple sugar glucose is broken down to produce energy. Mutations in the PGK1 gene reduce the activity of phosphoglycerate kinase, which disrupts energy production and leads to cell damage or cell death. It is unclear why this abnormality preferentially affects red blood cells and brain cells in some people and muscle cells in others. Researchers speculate that different PGK1 gene mutations may have varying effects on the activity of phosphoglycerate kinase in different types of cells. |
inheritance | Is phosphoglycerate kinase deficiency inherited ? | This condition is inherited in an X-linked recessive pattern. The PGK1 gene is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Females with one altered PGK1 gene, however, may have some features of phosphoglycerate kinase deficiency, such as anemia. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. |
treatment | What are the treatments for phosphoglycerate kinase deficiency ? | These resources address the diagnosis or management of phosphoglycerate kinase deficiency: - Children Living with Inherited Metabolic Diseases (CLIMB) (UK): Phosphoglycerate Kinase Deficiency - Genetic Testing Registry: Deficiency of phosphoglycerate kinase - Genetic Testing Registry: Phosphoglycerate kinase 1 deficiency These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) fumarase deficiency ? | Fumarase deficiency is a condition that primarily affects the nervous system, especially the brain. Affected infants may have an abnormally small head size (microcephaly), abnormal brain structure, severe developmental delay, weak muscle tone (hypotonia), and failure to gain weight and grow at the expected rate (failure to thrive). They may also experience seizures. Some people with this disorder have unusual facial features, including a prominent forehead (frontal bossing), low-set ears, a small jaw (micrognathia), widely spaced eyes (ocular hypertelorism), and a depressed nasal bridge. An enlarged liver and spleen (hepatosplenomegaly) may also be associated with this disorder, as well as an excess of red blood cells (polycythemia) or deficiency of white blood cells (leukopenia) in infancy. Affected individuals usually survive only a few months, but a few have lived into early adulthood. |
frequency | How many people are affected by fumarase deficiency ? | Fumarase deficiency is a very rare disorder. Approximately 100 affected individuals have been reported worldwide. Several were born in an isolated religious community in the southwestern United States. |
genetic changes | What are the genetic changes related to fumarase deficiency ? | The FH gene provides instructions for making an enzyme called fumarase (also known as fumarate hydratase). Fumarase participates in an important series of reactions known as the citric acid cycle or Krebs cycle, which allows cells to use oxygen and generate energy. Specifically, fumarase helps convert a molecule called fumarate to a molecule called malate. Mutations in the FH gene disrupt the enzyme's ability to help convert fumarate to malate, interfering with the function of this reaction in the citric acid cycle. Impairment of the process that generates energy for cells is particularly harmful to cells in the developing brain, and this impairment results in the signs and symptoms of fumarase deficiency. |
inheritance | Is fumarase deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for fumarase deficiency ? | These resources address the diagnosis or management of fumarase deficiency: - Gene Review: Gene Review: Fumarate Hydratase Deficiency - Genetic Testing Registry: Fumarase deficiency These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) 3-methylglutaconyl-CoA hydratase deficiency ? | 3-methylglutaconyl-CoA hydratase deficiency is an inherited condition that causes neurological problems. Beginning in infancy to early childhood, children with this condition often have delayed development of mental and motor skills (psychomotor delay), speech delay, involuntary muscle cramping (dystonia), and spasms and weakness of the arms and legs (spastic quadriparesis). Affected individuals can also have optic atrophy, which is the degeneration (atrophy) of nerve cells that carry visual information from the eyes to the brain. In some cases, signs and symptoms of 3-methylglutaconyl-CoA hydratase deficiency begin in adulthood, often in a person's twenties or thirties. These individuals have damage to a type of brain tissue called white matter (leukoencephalopathy), which likely contributes to progressive problems with speech (dysarthria), difficulty coordinating movements (ataxia), stiffness (spasticity), optic atrophy, and a decline in intellectual function (dementia). Affected individuals who show symptoms of 3-methylglutaconyl-CoA hydratase deficiency in childhood often go on to develop leukoencephalopathy and other neurological problems in adulthood. All people with 3-methylglutaconyl-CoA hydratase deficiency accumulate large amounts of a substance called 3-methylglutaconic acid in their body fluids. As a result, they have elevated levels of acid in their blood (metabolic acidosis) and excrete large amounts of acid in their urine (aciduria). 3-methylglutaconyl-CoA hydratase deficiency is one of a group of metabolic disorders that can be diagnosed by the presence of increased levels 3-methylglutaconic acid in urine (3-methylglutaconic aciduria). People with 3-methylglutaconyl-CoA hydratase deficiency also have high urine levels of another acid called 3-methylglutaric acid. |
frequency | How many people are affected by 3-methylglutaconyl-CoA hydratase deficiency ? | 3-methylglutaconyl-CoA hydratase deficiency is a rare disorder; at least 20 cases have been reported in the scientific literature. |
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