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What is (are) androgen insensitivity syndrome ? | Androgen insensitivity syndrome is a condition that affects sexual development before birth and during puberty. People with this condition are genetically male, with one X chromosome and one Y chromosome in each cell. Because their bodies are unable to respond to certain male sex hormones (called androgens), they may have mostly female sex characteristics or signs of both male and female sexual development. Complete androgen insensitivity syndrome occurs when the body cannot use androgens at all. People with this form of the condition have the external sex characteristics of females, but do not have a uterus and therefore do not menstruate and are unable to conceive a child (infertile). They are typically raised as females and have a female gender identity. Affected individuals have male internal sex organs (testes) that are undescended, which means they are abnormally located in the pelvis or abdomen. Undescended testes can become cancerous later in life if they are not surgically removed. People with complete androgen insensitivity syndrome also have sparse or absent hair in the pubic area and under the arms. The partial and mild forms of androgen insensitivity syndrome result when the body's tissues are partially sensitive to the effects of androgens. People with partial androgen insensitivity (also called Reifenstein syndrome) can have normal female sex characteristics, both male and female sex characteristics, or normal male sex characteristics. They may be raised as males or as females, and may have a male or a female gender identity. People with mild androgen insensitivity are born with male sex characteristics, but are often infertile and tend to experience breast enlargement at puberty. | androgen insensitivity syndrome |
How many people are affected by androgen insensitivity syndrome ? | Complete androgen insensitivity syndrome affects 2 to 5 per 100,000 people who are genetically male. Partial androgen insensitivity is thought to be at least as common as complete androgen insensitivity. Mild androgen insensitivity is much less common. | androgen insensitivity syndrome |
What are the genetic changes related to androgen insensitivity syndrome ? | Mutations in the AR gene cause androgen insensitivity syndrome. This gene provides instructions for making a protein called an androgen receptor. Androgen receptors allow cells to respond to androgens, which are hormones (such as testosterone) that direct male sexual development. Androgens and androgen receptors also have other important functions in both males and females, such as regulating hair growth and sex drive. Mutations in the AR gene prevent androgen receptors from working properly, which makes cells less responsive to androgens or prevents cells from using these hormones at all. Depending on the level of androgen insensitivity, an affected person's sex characteristics can vary from mostly female to mostly male. | androgen insensitivity syndrome |
Is androgen insensitivity syndrome inherited ? | This condition is inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. In genetic males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In genetic females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the disorder. Males are affected by X-linked recessive disorders much more frequently than females. About two-thirds of all cases of androgen insensitivity syndrome are inherited from mothers who carry an altered copy of the AR gene on one of their two X chromosomes. The remaining cases result from a new mutation that can occur in the mother's egg cell before the child is conceived or during early fetal development. | androgen insensitivity syndrome |
What are the treatments for androgen insensitivity syndrome ? | These resources address the diagnosis or management of androgen insensitivity syndrome: - Gene Review: Gene Review: Androgen Insensitivity Syndrome - Genetic Testing Registry: Androgen resistance syndrome - MedlinePlus Encyclopedia: Androgen Insensitivity Syndrome - MedlinePlus Encyclopedia: Intersex - MedlinePlus Encyclopedia: Reifenstein 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 | androgen insensitivity syndrome |
What is (are) congenital bilateral absence of the vas deferens ? | Congenital bilateral absence of the vas deferens occurs in males when the tubes that carry sperm out of the testes (the vas deferens) fail to develop properly. Although the testes usually develop and function normally, sperm cannot be transported through the vas deferens to become part of semen. As a result, men with this condition are unable to father children (infertile) unless they use assisted reproductive technologies. This condition has not been reported to affect sex drive or sexual performance. This condition can occur alone or as a sign of cystic fibrosis, an inherited disease of the mucus glands. Cystic fibrosis causes progressive damage to the respiratory system and chronic digestive system problems. Many men with congenital bilateral absence of the vas deferens do not have the other characteristic features of cystic fibrosis; however, some men with this condition may experience mild respiratory or digestive problems. | congenital bilateral absence of the vas deferens |
How many people are affected by congenital bilateral absence of the vas deferens ? | This condition is responsible for 1 percent to 2 percent of all infertility in men. | congenital bilateral absence of the vas deferens |
What are the genetic changes related to congenital bilateral absence of the vas deferens ? | Mutations in the CFTR gene cause congenital bilateral absence of the vas deferens. More than half of all men with this condition have mutations in the CFTR gene. Mutations in this gene also cause cystic fibrosis. When congenital bilateral absence of the vas deferens occurs with CFTR mutations, it is considered a form of atypical cystic fibrosis. The protein made from the CFTR gene forms a channel that transports negatively charged particles called chloride ions into and out of cells. The flow of chloride ions helps control the movement of water in tissues, which is necessary for the production of thin, freely flowing mucus. Mucus is a slippery substance that lubricates and protects the linings of the airways, digestive system, reproductive system, and other organs and tissues. Mutations in the CFTR gene disrupt the function of the chloride channels, preventing them from regulating the flow of chloride ions and water across cell membranes. As a result, cells in the male genital tract produce mucus that is abnormally thick and sticky. This mucus clogs the vas deferens as they are forming, causing them to deteriorate before birth. In instances of congenital bilateral absence of the vas deferens without a mutation in the CFTR gene, the cause of this condition is often unknown. Some cases are associated with other structural problems of the urinary tract. | congenital bilateral absence of the vas deferens |
Is congenital bilateral absence of the vas deferens inherited ? | When this condition is caused by mutations in the CFTR gene, it is inherited in an autosomal recessive pattern. This pattern of inheritance means that both copies of the gene in each cell have a mutation. Men with this condition who choose to father children through assisted reproduction have an increased risk of having a child with cystic fibrosis. If congenital absence of the vas deferens is not caused by mutations in CFTR, the risk of having children with cystic fibrosis is not increased. | congenital bilateral absence of the vas deferens |
What are the treatments for congenital bilateral absence of the vas deferens ? | These resources address the diagnosis or management of congenital bilateral absence of the vas deferens: - Gene Review: Gene Review: CFTR-Related Disorders - Genetic Testing Registry: Congenital bilateral absence of the vas deferens - MedlinePlus Encyclopedia: Infertility - MedlinePlus Encyclopedia: Pathway of sperm (image) - MedlinePlus Health Topic: Assisted Reproductive Technology 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 | congenital bilateral absence of the vas deferens |
What is (are) Leber hereditary optic neuropathy ? | Leber hereditary optic neuropathy (LHON) is an inherited form of vision loss. Although this condition usually begins in a person's teens or twenties, rare cases may appear in early childhood or later in adulthood. For unknown reasons, males are affected much more often than females. Blurring and clouding of vision are usually the first symptoms of LHON. These vision problems may begin in one eye or simultaneously in both eyes; if vision loss starts in one eye, the other eye is usually affected within several weeks or months. Over time, vision in both eyes worsens with a severe loss of sharpness (visual acuity) and color vision. This condition mainly affects central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces. Vision loss results from the death of cells in the nerve that relays visual information from the eyes to the brain (the optic nerve). Although central vision gradually improves in a small percentage of cases, in most cases the vision loss is profound and permanent. Vision loss is typically the only symptom of LHON; however, some families with additional signs and symptoms have been reported. In these individuals, the condition is described as "LHON plus." In addition to vision loss, the features of LHON plus can include movement disorders, tremors, and abnormalities of the electrical signals that control the heartbeat (cardiac conduction defects). Some affected individuals develop features similar to multiple sclerosis, which is a chronic disorder characterized by muscle weakness, poor coordination, numbness, and a variety of other health problems. | Leber hereditary optic neuropathy |
How many people are affected by Leber hereditary optic neuropathy ? | The prevalence of LHON in most populations is unknown. It affects 1 in 30,000 to 50,000 people in northeast England and Finland. | Leber hereditary optic neuropathy |
What are the genetic changes related to Leber hereditary optic neuropathy ? | Mutations in the MT-ND1, MT-ND4, MT-ND4L, or MT-ND6 gene can cause LHON. These genes are found in the DNA of cellular structures called mitochondria, which convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA, known as mitochondrial DNA or mtDNA. The genes associated with LHON each provide instructions for making a protein involved in normal mitochondrial function. These proteins are part of a large enzyme complex in mitochondria that helps convert oxygen, fats, and simple sugars to energy. Mutations in any of the genes disrupt this process. It remains unclear how these genetic changes cause the death of cells in the optic nerve and lead to the specific features of LHON. A significant percentage of people with a mutation that causes LHON do not develop any features of the disorder. Specifically, more than 50 percent of males with a mutation and more than 85 percent of females with a mutation never experience vision loss or related health problems. Additional factors may determine whether a person develops the signs and symptoms of this disorder. Environmental factors such as smoking and alcohol use may be involved, although studies have produced conflicting results. Researchers are also investigating whether changes in additional genes contribute to the development of signs and symptoms. | Leber hereditary optic neuropathy |
Is Leber hereditary optic neuropathy inherited ? | LHON has a mitochondrial pattern of inheritance, which is also known as maternal inheritance. This pattern of inheritance applies to genes contained in mtDNA. Because egg cells, but not sperm cells, contribute mitochondria to the developing embryo, children can only inherit disorders resulting from mtDNA mutations from their mother. These disorders can appear in every generation of a family and can affect both males and females, but fathers do not pass traits associated with changes in mtDNA to their children. Often, people who develop the features of LHON have no family history of the condition. Because a person may carry an mtDNA mutation without experiencing any signs or symptoms, it is hard to predict which members of a family who carry a mutation will eventually develop vision loss or other problems associated with LHON. It is important to note that all females with an mtDNA mutation, even those who do not have any signs or symptoms, will pass the genetic change to their children. | Leber hereditary optic neuropathy |
What are the treatments for Leber hereditary optic neuropathy ? | These resources address the diagnosis or management of Leber hereditary optic neuropathy: - Gene Review: Gene Review: Leber Hereditary Optic Neuropathy - Gene Review: Gene Review: Mitochondrial Disorders Overview - Genetic Testing Registry: Leber's optic atrophy - MedlinePlus Encyclopedia: Blindness - MedlinePlus Encyclopedia: Blindness - Resources 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 | Leber hereditary optic neuropathy |
What is (are) Netherton syndrome ? | Netherton syndrome is a disorder that affects the skin, hair, and immune system. Newborns with Netherton syndrome have skin that is red and scaly (ichthyosiform erythroderma), and the skin may leak fluid. Some affected infants are born with a tight, clear sheath covering their skin called a collodion membrane. This membrane is usually shed during the first few weeks of life. Because newborns with this disorder are missing the protection provided by normal skin, they are at risk of becoming dehydrated and developing infections in the skin or throughout the body (sepsis), which can be life-threatening. Affected babies may also fail to grow and gain weight at the expected rate (failure to thrive). The health of older children and adults with Netherton syndrome usually improves, although they often remain underweight and of short stature. After infancy, the severity of the skin abnormalities varies among people with Netherton syndrome and can fluctuate over time. The skin may continue to be red and scaly, especially during the first few years of life. Some affected individuals have intermittent redness or experience outbreaks of a distinctive skin abnormality called ichthyosis linearis circumflexa, involving patches of multiple ring-like lesions. The triggers for the outbreaks are not known, but researchers suggest that stress or infections may be involved. Itchiness is a common problem for affected individuals, and scratching can lead to frequent infections. Dead skin cells are shed at an abnormal rate and often accumulate in the ear canals, which can affect hearing if not removed regularly. The skin is abnormally absorbent of substances such as lotions and ointments, which can result in excessive blood levels of some topical medications. Because the ability of the skin to protect against heat and cold is impaired, affected individuals may have difficulty regulating their body temperature. People with Netherton syndrome have hair that is fragile and breaks easily. Some strands of hair vary in diameter, with thicker and thinner spots. This feature is known as bamboo hair, trichorrhexis nodosa, or trichorrhexis invaginata. In addition to the hair on the scalp, the eyelashes and eyebrows may be affected. The hair abnormality in Netherton syndrome may not be noticed in infancy because babies often have sparse hair. Most people with Netherton syndrome have immune system-related problems such as food allergies, hay fever, asthma, or an inflammatory skin disorder called eczema. | Netherton syndrome |
How many people are affected by Netherton syndrome ? | Netherton syndrome is estimated to affect 1 in 200,000 newborns. | Netherton syndrome |
What are the genetic changes related to Netherton syndrome ? | Netherton syndrome is caused by mutations in the SPINK5 gene. This gene provides instructions for making a protein called LEKT1. LEKT1 is a type of serine peptidase inhibitor. Serine peptidase inhibitors control the activity of enzymes called serine peptidases, which break down other proteins. LEKT1 is found in the skin and in the thymus, which is a gland located behind the breastbone that plays an important role in the immune system by producing white blood cells called lymphocytes. LEKT1 controls the activity of certain serine peptidases in the outer layer of skin (the epidermis), especially the tough outer surface known as the stratum corneum, which provides a sturdy barrier between the body and its environment. Serine peptidase enzymes are involved in normal skin shedding by helping to break the connections between cells of the stratum corneum. LEKT1 is also involved in normal hair growth, the development of lymphocytes in the thymus, and the control of peptidases that trigger immune system function. Mutations in the SPINK5 gene result in a LEKT1 protein that is unable to control serine peptidase activity. The lack of LEKT1 function allows the serine peptidases to be abnormally active and break down too many proteins in the stratum corneum. As a result, too much skin shedding takes place, and the stratum corneum is too thin and breaks down easily, resulting in the skin abnormalities that occur in Netherton syndrome. Loss of LEKT1 function also results in abnormal hair growth and immune dysfunction that leads to allergies, asthma, and eczema. | Netherton syndrome |
Is Netherton 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. | Netherton syndrome |
What are the treatments for Netherton syndrome ? | These resources address the diagnosis or management of Netherton syndrome: - Genetic Testing Registry: Netherton 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 | Netherton syndrome |
What is (are) Down syndrome ? | Down syndrome is a chromosomal condition that is associated with intellectual disability, a characteristic facial appearance, and weak muscle tone (hypotonia) in infancy. All affected individuals experience cognitive delays, but the intellectual disability is usually mild to moderate. People with Down syndrome may have a variety of birth defects. About half of all affected children are born with a heart defect. Digestive abnormalities, such as a blockage of the intestine, are less common. Individuals with Down syndrome have an increased risk of developing several medical conditions. These include gastroesophageal reflux, which is a backflow of acidic stomach contents into the esophagus, and celiac disease, which is an intolerance of a wheat protein called gluten. About 15 percent of people with Down syndrome have an underactive thyroid gland (hypothyroidism). The thyroid gland is a butterfly-shaped organ in the lower neck that produces hormones. Individuals with Down syndrome also have an increased risk of hearing and vision problems. Additionally, a small percentage of children with Down syndrome develop cancer of blood-forming cells (leukemia). Delayed development and behavioral problems are often reported in children with Down syndrome. Affected individuals' speech and language develop later and more slowly than in children without Down syndrome, and affected individuals' speech may be more difficult to understand. Behavioral issues can include attention problems, obsessive/compulsive behavior, and stubbornness or tantrums. A small percentage of people with Down syndrome are also diagnosed with developmental conditions called autism spectrum disorders, which affect communication and social interaction. People with Down syndrome often experience a gradual decline in thinking ability (cognition) as they age, usually starting around age 50. Down syndrome is also associated with an increased risk of developing Alzheimer disease, a brain disorder that results in a gradual loss of memory, judgment, and ability to function. Approximately half of adults with Down syndrome develop Alzheimer disease. Although Alzheimer disease is usually a disorder that occurs in older adults, people with Down syndrome usually develop this condition in their fifties or sixties. | Down syndrome |
How many people are affected by Down syndrome ? | Down syndrome occurs in about 1 in 800 newborns. About 5,300 babies with Down syndrome are born in the United States each year, and an estimated 250,000 people in this country have the condition. Although women of any age can have a child with Down syndrome, the chance of having a child with this condition increases as a woman gets older. | Down syndrome |
What are the genetic changes related to Down syndrome ? | Most cases of Down syndrome result from trisomy 21, which means each cell in the body has three copies of chromosome 21 instead of the usual two copies. Less commonly, Down syndrome occurs when part of chromosome 21 becomes attached (translocated) to another chromosome during the formation of reproductive cells (eggs and sperm) in a parent or very early in fetal development. Affected people have two normal copies of chromosome 21 plus extra material from chromosome 21 attached to another chromosome, resulting in three copies of genetic material from chromosome 21. Affected individuals with this genetic change are said to have translocation Down syndrome. A very small percentage of people with Down syndrome have an extra copy of chromosome 21 in only some of the body's cells. In these people, the condition is called mosaic Down syndrome. Researchers believe that having extra copies of genes on chromosome 21 disrupts the course of normal development, causing the characteristic features of Down syndrome and the increased risk of health problems associated with this condition. | Down syndrome |
Is Down syndrome inherited ? | Most cases of Down syndrome are not inherited. When the condition is caused by trisomy 21, the chromosomal abnormality occurs as a random event during the formation of reproductive cells in a parent. The abnormality usually occurs in egg cells, but it occasionally occurs in sperm cells. An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 21. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 21 in each of the body's cells. People with translocation Down syndrome can inherit the condition from an unaffected parent. The parent carries a rearrangement of genetic material between chromosome 21 and another chromosome. This rearrangement is called a balanced translocation. No genetic material is gained or lost in a balanced translocation, so these chromosomal changes usually do not cause any health problems. However, as this translocation is passed to the next generation, it can become unbalanced. People who inherit an unbalanced translocation involving chromosome 21 may have extra genetic material from chromosome 21, which causes Down syndrome. Like trisomy 21, mosaic Down syndrome is not inherited. It occurs as a random event during cell division early in fetal development. As a result, some of the body's cells have the usual two copies of chromosome 21, and other cells have three copies of this chromosome. | Down syndrome |
What are the treatments for Down syndrome ? | These resources address the diagnosis or management of Down syndrome: - GeneFacts: Down Syndrome: Diagnosis - GeneFacts: Down Syndrome: Management - Genetic Testing Registry: Complete trisomy 21 syndrome - National Down Syndrome Congress: Health Care - National Down Syndrome Congress: Speech and Language - National Down Syndrome Society: Health Care - National Down Syndrome Society: Therapies and Development 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 | Down syndrome |
What is (are) paroxysmal nocturnal hemoglobinuria ? | Paroxysmal nocturnal hemoglobinuria is an acquired disorder that leads to the premature death and impaired production of blood cells. The disorder affects red blood cells (erythrocytes), which carry oxygen; white blood cells (leukocytes), which protect the body from infection; and platelets (thrombocytes), which are involved in blood clotting. Paroxysmal nocturnal hemoglobinuria affects both sexes equally, and can occur at any age, although it is most often diagnosed in young adulthood. People with paroxysmal nocturnal hemoglobinuria have sudden, recurring episodes of symptoms (paroxysmal symptoms), which may be triggered by stresses on the body, such as infections or physical exertion. During these episodes, red blood cells are prematurely destroyed (hemolysis). Affected individuals may pass dark-colored urine due to the presence of hemoglobin, the oxygen-carrying protein in blood. The abnormal presence of hemoglobin in the urine is called hemoglobinuria. In many, but not all cases, hemoglobinuria is most noticeable in the morning, upon passing urine that has accumulated in the bladder during the night (nocturnal). The premature destruction of red blood cells results in a deficiency of these cells in the blood (hemolytic anemia), which can cause signs and symptoms such as fatigue, weakness, abnormally pale skin (pallor), shortness of breath, and an increased heart rate. People with paroxysmal nocturnal hemoglobinuria may also be prone to infections due to a deficiency of white blood cells. Abnormal platelets associated with paroxysmal nocturnal hemoglobinuria can cause problems in the blood clotting process. As a result, people with this disorder may experience abnormal blood clotting (thrombosis), especially in large abdominal veins; or, less often, episodes of severe bleeding (hemorrhage). Individuals with paroxysmal nocturnal hemoglobinuria are at increased risk of developing cancer in blood-forming cells (leukemia). In some cases, people who have been treated for another blood disease called aplastic anemia may develop paroxysmal nocturnal hemoglobinuria. | paroxysmal nocturnal hemoglobinuria |
How many people are affected by paroxysmal nocturnal hemoglobinuria ? | Paroxysmal nocturnal hemoglobinuria is a rare disorder, estimated to affect between 1 and 5 per million people. | paroxysmal nocturnal hemoglobinuria |
What are the genetic changes related to paroxysmal nocturnal hemoglobinuria ? | Mutations in the PIGA gene cause paroxysmal nocturnal hemoglobinuria. The PIGA gene provides instructions for making a protein called phosphatidylinositol glycan class A. This protein takes part in a series of steps that produce a molecule called GPI anchor. GPI anchor attaches many different proteins to the cell membrane, thereby ensuring that these proteins are available when needed at the surface of the cell. Some gene mutations are acquired during a person's lifetime and are present only in certain cells. These changes, which are called somatic mutations, are not inherited. In people with paroxysmal nocturnal hemoglobinuria, somatic mutations of the PIGA gene occur in blood-forming cells called hematopoietic stem cells, which are found mainly in the bone marrow. These mutations result in the production of abnormal blood cells. As the abnormal hematopoietic stem cells multiply, increasing numbers of abnormal blood cells are formed, alongside normal blood cells produced by normal hematopoietic stem cells. The premature destruction of red blood cells seen in paroxysmal nocturnal hemoglobinuria is caused by a component of the immune system called complement. Complement consists of a group of proteins that work together to destroy foreign invaders such as bacteria and viruses. To protect the individual's own cells from being destroyed, this process is tightly controlled by complement-regulating proteins. Complement-regulating proteins normally protect red blood cells from destruction by complement. In people with paroxysmal nocturnal hemoglobinuria, however, abnormal red blood cells are missing two important complement-regulating proteins that need the GPI anchor protein to attach them to the cell membrane. These red blood cells are prematurely destroyed, leading to hemolytic anemia. Research suggests that certain abnormal white blood cells that are also part of the immune system may mistakenly attack normal blood-forming cells, in a malfunction called an autoimmune process. In addition, abnormal hematopoietic stem cells in people with paroxysmal nocturnal hemoglobinuria may be less susceptible than normal cells to a process called apoptosis, which causes cells to self-destruct when they are damaged or unneeded. These features of the disorder may increase the proportion of abnormal blood cells in the body. The proportion of abnormal blood cells affects the severity of the signs and symptoms of paroxysmal nocturnal hemoglobinuria, including the risk of hemoglobinuria and thrombosis. | paroxysmal nocturnal hemoglobinuria |
Is paroxysmal nocturnal hemoglobinuria inherited ? | This condition is acquired, rather than inherited. It results from new mutations in the PIGA gene, and generally occurs in people with no previous history of the disorder in their family. The condition is not passed down to children of affected individuals. | paroxysmal nocturnal hemoglobinuria |
What are the treatments for paroxysmal nocturnal hemoglobinuria ? | These resources address the diagnosis or management of paroxysmal nocturnal hemoglobinuria: - Duke University School of Medicine: Hemostasis & Thrombosis Center - Genetic Testing Registry: Paroxysmal nocturnal hemoglobinuria - MedlinePlus Encyclopedia: Paroxysmal nocturnal hemoglobinuria (PNH) - Memorial Sloan-Kettering Cancer Center These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | paroxysmal nocturnal hemoglobinuria |
What is (are) congenital mirror movement disorder ? | Congenital mirror movement disorder is a condition in which intentional movements of one side of the body are mirrored by involuntary movements of the other side. For example, when an affected individual makes a fist with the right hand, the left hand makes a similar movement. The mirror movements in this disorder primarily involve the upper limbs, especially the hands and fingers. This pattern of movements is present from infancy or early childhood and usually persists throughout life, without other associated signs and symptoms. Intelligence and lifespan are not affected. People with congenital mirror movement disorder can have some difficulty with certain activities of daily living, particularly with those requiring different movements in each hand, such as typing on a keyboard. They may experience discomfort or pain in the upper limbs during prolonged use of the hands. The extent of the mirror movements in this disorder can vary, even within the same family. In most cases, the involuntary movements are noticeable but less pronounced than the corresponding voluntary movements. The extent of the movements typically stay the same throughout the lifetime of an affected individual. Mirror movements can also occur in people who do not have congenital mirror movement disorder. Mild mirror movements are common during the normal development of young children and typically disappear before age 7. They can also develop later in life in people with neurodegenerative disorders such as Parkinson disease. Mirror movements may also be present in certain other conditions with a wider range of signs and symptoms (syndromes). | congenital mirror movement disorder |
How many people are affected by congenital mirror movement disorder ? | Congenital mirror movement disorder is a very rare disorder. Its prevalence is thought to be less than 1 in 1 million. Researchers suggest that some mildly affected individuals may never be diagnosed. | congenital mirror movement disorder |
What are the genetic changes related to congenital mirror movement disorder ? | Congenital mirror movement disorder can be caused by mutations in the DCC or RAD51 gene; mutations in these genes account for a total of about 35 percent of cases. Mutations in other genes that have not been identified likely account for other cases of this disorder. The DCC gene provides instructions for making a protein called the netrin-1 receptor, which is involved in the development of the nervous system. This receptor attaches (binds) to a substance called netrin-1, fitting together like a lock and its key. The binding of netrin-1 to its receptor triggers signaling that helps direct the growth of specialized nerve cell extensions called axons, which transmit nerve impulses that signal muscle movement. Normally, signals from each half of the brain control movements on the opposite side of the body. Binding of netrin-1 to its receptor inhibits axons from developing in ways that would carry movement signals from each half of the brain to the same side of the body. Mutations in the DCC gene result in an impaired or missing netrin-1 receptor protein. A shortage of functional netrin-1 receptor protein impairs control of axon growth during nervous system development. As a result, movement signals from each half of the brain are abnormally transmitted to both sides of the body, leading to mirror movements. The RAD51 gene provides instructions for making a protein that is also thought to be involved in the development of nervous system functions that control movement, but its role in this development is unclear. Mutations in the RAD51 gene result in a missing or impaired RAD51 protein, but it is unknown how a shortage of functional RAD51 protein affects nervous system development and leads to the signs and symptoms of congenital mirror movement disorder. | congenital mirror movement disorder |
Is congenital mirror movement disorder inherited ? | In most cases, including those caused by mutations in the DCC or RAD51 gene, this condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the altered gene. Some people who have the altered gene never develop the condition, a situation known as reduced penetrance. Research suggests that in rare cases, this condition may be 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. | congenital mirror movement disorder |
What are the treatments for congenital mirror movement disorder ? | These resources address the diagnosis or management of congenital mirror movement disorder: - Gene Review: Gene Review: Congenital Mirror Movements - Genetic Testing Registry: Mirror movements 2 - Genetic Testing Registry: Mirror movements, congenital - KidsHealth: Occupational Therapy 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 | congenital mirror movement disorder |
What is (are) Knobloch syndrome ? | Knobloch syndrome is a rare condition characterized by severe vision problems and a skull defect. A characteristic feature of Knobloch syndrome is extreme nearsightedness (high myopia). In addition, several other eye abnormalities are common in people with this condition. Most affected individuals have vitreoretinal degeneration, which is breakdown (degeneration) of two structures in the eye called the vitreous and the retina. The vitreous is the gelatin-like substance that fills the eye, and the retina is the light-sensitive tissue at the back of the eye. Vitreoretinal degeneration often leads to separation of the retina from the back of the eye (retinal detachment). Affected individuals may also have abnormalities in the central area 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. Due to abnormalities in the vitreous, retina, and macula, people with Knobloch syndrome often develop blindness in one or both eyes. Another characteristic feature of Knobloch syndrome is a skull defect called an occipital encephalocele, which is a sac-like protrusion of the brain (encephalocele) through a defect in the bone at the base of the skull (occipital bone). Some affected individuals have been diagnosed with a different skull defect in the occipital region, and it is unclear whether the defect is always a true encephalocele. In other conditions, encephaloceles may be associated with intellectual disability; however, most people with Knobloch syndrome have normal intelligence. | Knobloch syndrome |
How many people are affected by Knobloch syndrome ? | Knobloch syndrome is a rare condition. However, the exact prevalence of the condition is unknown. | Knobloch syndrome |
What are the genetic changes related to Knobloch syndrome ? | Mutations in the COL18A1 gene can cause Knobloch syndrome. The COL18A1 gene provides instructions for making a protein that forms collagen XVIII, which is found in the basement membranes of tissues throughout the body. Basement membranes are thin, sheet-like structures that separate and support cells in these tissues. Collagen XVIII is found in the basement membranes of several parts of the eye, including the vitreous and retina, among other tissues. Little is known about the function of this protein, but it appears to be involved in normal development of the eye. Several mutations in the COL18A1 gene have been identified in people with Knobloch syndrome. Most COL18A1 gene mutations lead to an abnormally short version of the genetic blueprint used to make the collagen XVIII protein. Although the process is unclear, the COL18A1 gene mutations result in the loss of collagen XVIII protein, which likely causes the signs and symptoms of Knobloch syndrome. When the condition is caused by COL18A1 gene mutations, it is sometimes referred to as Knobloch syndrome type I. Research indicates that mutations in at least two other genes that have not been identified may cause Knobloch syndrome types II and III. Although they are caused by alterations in different genes, the three types of the condition have similar signs and symptoms. | Knobloch syndrome |
Is Knobloch 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. | Knobloch syndrome |
What are the treatments for Knobloch syndrome ? | These resources address the diagnosis or management of Knobloch syndrome: - American Academy of Ophthalmology: Eye Smart - Genetic Testing Registry: Knobloch syndrome 1 - JAMA Patient Page: Retinal Detachment - National Eye Institute: Facts About Retinal Detachment - Prevent Blindness America: Retinal Tears and Detachments 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 | Knobloch syndrome |
What is (are) potassium-aggravated myotonia ? | Potassium-aggravated myotonia is a disorder that affects muscles used for movement (skeletal muscles). Beginning in childhood or adolescence, people with this condition experience bouts of sustained muscle tensing (myotonia) that prevent muscles from relaxing normally. Myotonia causes muscle stiffness that worsens after exercise and may be aggravated by eating potassium-rich foods such as bananas and potatoes. Stiffness occurs in skeletal muscles throughout the body. Potassium-aggravated myotonia ranges in severity from mild episodes of muscle stiffness to severe, disabling disease with frequent attacks. Unlike some other forms of myotonia, potassium-aggravated myotonia is not associated with episodes of muscle weakness. | potassium-aggravated myotonia |
How many people are affected by potassium-aggravated myotonia ? | This condition appears to be rare; it has been reported in only a few individuals and families worldwide. | potassium-aggravated myotonia |
What are the genetic changes related to potassium-aggravated myotonia ? | Mutations in the SCN4A gene cause potassium-aggravated myotonia. The SCN4A gene provides instructions for making a protein that is critical for the normal function of skeletal muscle cells. For the body to move normally, skeletal muscles must tense (contract) and relax in a coordinated way. Muscle contractions are triggered by the flow of positively charged atoms (ions), including sodium, into skeletal muscle cells. The SCN4A protein forms channels that control the flow of sodium ions into these cells. Mutations in the SCN4A gene alter the usual structure and function of sodium channels. The altered channels cannot properly regulate ion flow, increasing the movement of sodium ions into skeletal muscle cells. The influx of extra sodium ions triggers prolonged muscle contractions, which are the hallmark of myotonia. | potassium-aggravated myotonia |
Is potassium-aggravated myotonia inherited ? | Potassium-aggravated myotonia 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 a mutation in the SCN4A gene from one affected parent. Other cases result from new mutations in the gene. These cases occur in people with no history of the disorder in their family. | potassium-aggravated myotonia |
What are the treatments for potassium-aggravated myotonia ? | These resources address the diagnosis or management of potassium-aggravated myotonia: - Genetic Testing Registry: Potassium aggravated myotonia 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 | potassium-aggravated myotonia |
What is (are) maternally inherited diabetes and deafness ? | Maternally inherited diabetes and deafness (MIDD) is a form of diabetes that is often accompanied by hearing loss, especially of high tones. The diabetes in MIDD is characterized by high blood sugar levels (hyperglycemia) resulting from a shortage of the hormone insulin, which regulates the amount of sugar in the blood. In MIDD, the diabetes and hearing loss usually develop in mid-adulthood, although the age that they occur varies from childhood to late adulthood. Typically, hearing loss occurs before diabetes. Some people with MIDD develop an eye disorder called macular retinal dystrophy, which is characterized by colored patches in the light-sensitive tissue that lines the back of the eye (the retina). This disorder does not usually cause vision problems in people with MIDD. Individuals with MIDD also may experience muscle cramps or weakness, particularly during exercise; heart problems; kidney disease; and constipation. Individuals with MIDD are often shorter than their peers. | maternally inherited diabetes and deafness |
How many people are affected by maternally inherited diabetes and deafness ? | About 1 percent of people with diabetes have MIDD. The condition is most common in the Japanese population and has been found in populations worldwide. | maternally inherited diabetes and deafness |
What are the genetic changes related to maternally inherited diabetes and deafness ? | Mutations in the MT-TL1, MT-TK, or MT-TE gene cause MIDD. These genes are found in mitochondrial DNA, which is part of cellular structures called mitochondria. Although most DNA is packaged in chromosomes within the cell nucleus, mitochondria also have a small amount of their own DNA (known as mitochondrial DNA or mtDNA). The MT-TL1, MT-TK, and MT-TE genes provide instructions for making molecules called transfer RNAs (tRNAs), which are chemical cousins of DNA. These molecules help assemble protein building blocks (amino acids) into functioning proteins. The MT-TL1 gene provides instructions for making a specific form of tRNA that is designated as tRNALeu(UUR). During protein assembly, this molecule attaches to the amino acid leucine (Leu) and inserts it into the appropriate locations in the growing protein. Similarly, the protein produced from the MT-TK gene, called tRNALys, attaches to the amino acid lysine (Lys) and inserts it into proteins being assembled. Also, the protein produced from the MT-TE gene, called tRNAGlu, attaches to the amino acid glutamic acid (Glu) and adds it to growing proteins. These tRNA molecules are present only in mitochondria, and they help assemble proteins that are involved in producing energy for cells. In certain cells in the pancreas called beta cells, mitochondria also play a role in controlling the amount of sugar (glucose) in the bloodstream. In response to high glucose levels, mitochondria help trigger the release of insulin, which stimulates cells to take up glucose from the blood. Mutations in the MT-TL1, MT-TK, or MT-TE gene reduce the ability of tRNA to add amino acids to growing proteins, which slows protein production in mitochondria and impairs their functioning. Researchers believe that the disruption of mitochondrial function lessens the ability of mitochondria to help trigger insulin release. In people with this condition, diabetes results when the beta cells do not produce enough insulin to regulate blood sugar effectively. Researchers have not determined how the mutations lead to hearing loss or the other features of MIDD. | maternally inherited diabetes and deafness |
Is maternally inherited diabetes and deafness inherited ? | MIDD is inherited in a mitochondrial pattern, which is also known as maternal inheritance. This pattern of inheritance applies to genes contained in mtDNA. Because egg cells, but not sperm cells, contribute mitochondria to the developing embryo, children can only inherit disorders resulting from mtDNA mutations from their mother. These disorders can appear in every generation of a family and can affect both males and females, but fathers do not pass traits associated with changes in mtDNA to their children. Most of the body's cells contain thousands of mitochondria, each with one or more copies of mtDNA. These cells can have a mix of mitochondria containing mutated and unmutated DNA (heteroplasmy). The severity of MIDD is thought to be associated with the percentage of mitochondria with the mtDNA mutation. | maternally inherited diabetes and deafness |
What are the treatments for maternally inherited diabetes and deafness ? | These resources address the diagnosis or management of MIDD: - Genetic Testing Registry: Diabetes-deafness syndrome maternally transmitted 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 | maternally inherited diabetes and deafness |
What is (are) Krabbe disease ? | Krabbe disease (also called globoid cell leukodystrophy) is a degenerative disorder that affects the nervous system. It is caused by the shortage (deficiency) of an enzyme called galactosylceramidase. This enzyme deficiency impairs the growth and maintenance of myelin, the protective covering around certain nerve cells that ensures the rapid transmission of nerve impulses. Krabbe disease is part of a group of disorders known as leukodystrophies, which result from the loss of myelin (demyelination). This disorder is also characterized by the abnormal presence of globoid cells, which are globe-shaped cells that usually have more than one nucleus. The symptoms of Krabbe disease usually begin before the age of 1 year (the infantile form). Initial signs and symptoms typically include irritability, muscle weakness, feeding difficulties, episodes of fever without any sign of infection, stiff posture, and slowed mental and physical development. As the disease progresses, muscles continue to weaken, affecting the infant's ability to move, chew, swallow, and breathe. Affected infants also experience vision loss and seizures. Less commonly, onset of Krabbe disease can occur in childhood, adolescence, or adulthood (late-onset forms). Visual problems and walking difficulties are the most common initial symptoms in this form of the disorder, however, signs and symptoms vary considerably among affected individuals. | Krabbe disease |
How many people are affected by Krabbe disease ? | In the United States, Krabbe disease affects about 1 in 100,000 individuals. A higher incidence (6 cases per 1,000 people) has been reported in a few isolated communities in Israel. | Krabbe disease |
What are the genetic changes related to Krabbe disease ? | Mutations in the GALC gene cause Krabbe disease. These mutations cause a deficiency of the enzyme galactosylceramidase. This deficiency leads to a progressive loss of myelin that covers many nerves. Without myelin, nerves in the brain and other parts of the body cannot function properly, leading to the signs and symptoms of Krabbe disease. | Krabbe disease |
Is Krabbe disease inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | Krabbe disease |
What are the treatments for Krabbe disease ? | These resources address the diagnosis or management of Krabbe disease: - Baby's First Test - Gene Review: Gene Review: Krabbe Disease - Genetic Testing Registry: Galactosylceramide beta-galactosidase deficiency - MedlinePlus Encyclopedia: Krabbe 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 | Krabbe disease |
What is (are) Simpson-Golabi-Behmel syndrome ? | Simpson-Golabi-Behmel syndrome is a condition that affects many parts of the body and occurs primarily in males. This condition is classified as an overgrowth syndrome, which means that affected infants are considerably larger than normal at birth (macrosomia) and continue to grow and gain weight at an unusual rate. The other signs and symptoms of Simpson-Golabi-Behmel syndrome vary widely. The most severe cases are life-threatening before birth or in infancy, whereas people with milder cases often live into adulthood. People with Simpson-Golabi-Behmel syndrome have distinctive facial features including widely spaced eyes (ocular hypertelorism), an unusually large mouth (macrostomia), a large tongue (macroglossia) that may have a deep groove or furrow down the middle, a broad nose with an upturned tip, and abnormalities affecting the roof of the mouth (the palate). The facial features are often described as "coarse" in older children and adults with this condition. Other features of Simpson-Golabi-Behmel syndrome involve the chest and abdomen. Affected infants may be born with one or more extra nipples, an abnormal opening in the muscle covering the abdomen (diastasis recti), a soft out-pouching around the belly-button (an umbilical hernia), or a hole in the diaphragm (a diaphragmatic hernia) that allows the stomach and intestines to move into the chest and crowd the developing heart and lungs. Simpson-Golabi-Behmel syndrome can also cause heart defects, malformed or abnormally large kidneys, an enlarged liver and spleen (hepatosplenomegaly), and skeletal abnormalities. Additionally, the syndrome can affect the development of the gastrointestinal system, urinary system, and genitalia. Some people with this condition have mild to severe intellectual disability, while others have normal intelligence. About 10 percent of people with Simpson-Golabi-Behmel syndrome develop cancerous or noncancerous tumors in early childhood. The most common tumors are a rare form of kidney cancer called Wilms tumor and a cancerous tumor called a neuroblastoma that arises in developing nerve cells. | Simpson-Golabi-Behmel syndrome |
How many people are affected by Simpson-Golabi-Behmel syndrome ? | The incidence of Simpson-Golabi-Behmel syndrome is unknown. At least 130 people worldwide have been diagnosed with this disorder. | Simpson-Golabi-Behmel syndrome |
What are the genetic changes related to Simpson-Golabi-Behmel syndrome ? | Mutations in the GPC3 gene are responsible for some cases of Simpson-Golabi-Behmel syndrome. This gene provides instructions for making a protein called glypican 3, which is involved in the regulation of cell growth and division (cell proliferation). Researchers believe that the GPC3 protein can also cause certain cells to self-destruct (undergo apoptosis) when they are no longer needed, which can help establish the body's shape. GPC3 mutations can delete part or all of the gene, or alter the structure of glypican 3. These mutations prevent the protein from performing its usual functions, which may contribute to an increased rate of cell growth and cell division starting before birth. It is unclear, however, how a shortage of functional glypican 3 causes overgrowth of the entire body and the other abnormalities characteristic of Simpson-Golabi-Behmel syndrome. Some individuals with Simpson-Golabi-Behmel syndrome do not have identified mutations in the GPC3 gene. In these cases, the cause of the condition is unknown. | Simpson-Golabi-Behmel syndrome |
Is Simpson-Golabi-Behmel syndrome inherited ? | This condition is inherited in an X-linked pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. Because females have two copies of the X chromosome, one altered copy of the gene in each cell usually leads to less severe symptoms in females than in males, or it may cause no symptoms at all. Some females who have one altered copy of the GPC3 gene have distinctive facial features including an upturned nose, a wide mouth, and a prominent chin. Their fingernails may be malformed and they can have extra nipples. Skeletal abnormalities, including extra spinal bones (vertebrae), are also possible in affected females. Other females who carry one altered copy of the GPC3 gene do not have these features or any other medical problems associated with Simpson-Golabi-Behmel syndrome. | Simpson-Golabi-Behmel syndrome |
What are the treatments for Simpson-Golabi-Behmel syndrome ? | These resources address the diagnosis or management of Simpson-Golabi-Behmel syndrome: - Gene Review: Gene Review: Simpson-Golabi-Behmel Syndrome Type 1 - Genetic Testing Registry: Simpson-Golabi-Behmel syndrome - MedlinePlus Encyclopedia: Diastasis Recti - MedlinePlus Encyclopedia: Macrosomia 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 | Simpson-Golabi-Behmel syndrome |
What is (are) surfactant dysfunction ? | Surfactant dysfunction is a lung disorder that causes breathing problems. This condition results from abnormalities in the composition or function of surfactant, a mixture of certain fats (called phospholipids) and proteins that lines the lung tissue and makes breathing easy. Without normal surfactant, the tissue surrounding the air sacs in the lungs (the alveoli) sticks together (because of a force called surface tension) after exhalation, causing the alveoli to collapse. As a result, filling the lungs with air on each breath becomes very difficult, and the delivery of oxygen to the body is impaired. The signs and symptoms of surfactant dysfunction can vary in severity. The most severe form of this condition causes respiratory distress syndrome in newborns. Affected babies have extreme difficulty breathing and are unable to get enough oxygen. The lack of oxygen can damage the baby's brain and other organs. This syndrome leads to respiratory failure, and most babies with this form of the condition do not survive more than a few months. Less severe forms of surfactant dysfunction cause gradual onset of breathing problems in children or adults. Signs and symptoms of these milder forms are abnormally rapid breathing (tachypnea); low concentrations of oxygen in the blood (hypoxemia); and an inability to grow or gain weight at the expected rate (failure to thrive). There are several types of surfactant dysfunction, which are identified by the genetic cause of the condition. One type, called SP-B deficiency, causes respiratory distress syndrome in newborns. Other types, known as SP-C dysfunction and ABCA3 deficiency, have signs and symptoms that range from mild to severe. | surfactant dysfunction |
How many people are affected by surfactant dysfunction ? | One type of surfactant dysfunction, SP-B deficiency, is estimated to occur in 1 in 1 million newborns worldwide. The prevalence of surfactant dysfunction due to other causes is unknown. | surfactant dysfunction |
What are the genetic changes related to surfactant dysfunction ? | Surfactant dysfunction is caused by mutations in one of several genes, including SFTPB, SFTPC, and ABCA3. Each of these genes is involved in the production of surfactant. The production and release of surfactant is a complex process. The phospholipids and proteins that make up surfactant are packaged in cellular structures known as lamellar bodies. These structures are also important for some processing of surfactant proteins, which is necessary for the proteins to mature and become functional. Surfactant is released from the lung cells and spreads across the tissue that surrounds alveoli. This substance lowers surface tension, which keeps the alveoli from collapsing after exhalation and makes breathing easy. The SFTPB and SFTPC genes provide instructions for making surfactant protein-B (SP-B) and surfactant protein-C (SP-C), respectively, two of the four proteins in surfactant. These two proteins help spread the surfactant across the surface of the lung tissue, aiding in the surface tension-lowering property of surfactant. In addition, SP-B plays a role in the formation of lamellar bodies. Mutations in the SFTPB gene cause a type of surfactant dysfunction sometimes referred to as SP-B deficiency. These mutations lead to a reduction in or absence of mature SP-B. In addition, SFTPB gene mutations cause abnormal processing of SP-C, resulting in a lack of mature SP-C and a buildup of unprocessed forms of SP-C. These changes lead to abnormal surfactant composition and decreased surfactant function. The loss of functional surfactant raises surface tension in the alveoli, causing severe breathing problems. The combination of SP-B and SP-C dysfunction may explain why the signs and symptoms of SP-B deficiency are so severe. Mutations in the SFTPC gene are involved in a type of surfactant dysfunction sometimes called SP-C dysfunction. These mutations result in a reduction or absence of mature SP-C and the buildup of abnormal forms of SP-C. It is unclear which of these outcomes causes the signs and symptoms of SP-C dysfunction. Lack of mature SP-C can lead to abnormal composition of surfactant and decreased surfactant function. Alternatively, research suggests that abnormally processed SP-C proteins form the wrong three-dimensional shape and accumulate inside the lung cells. These misfolded proteins may trigger a cellular response that results in cell damage and death. This damage may disrupt surfactant production and release. The ABCA3 gene provides instructions for making a protein that is found in the membrane that surrounds lamellar bodies. The ABCA3 protein transports phospholipids into lamellar bodies where they form surfactant. The ABCA3 protein also appears to be involved in the formation of lamellar bodies. ABCA3 gene mutations, which cause a type of surfactant dysfunction sometimes referred to as ABCA3 deficiency, lead to reduction or absence of the protein's function. Without ABCA3 protein function, the transport of surfactant phospholipids is decreased. In addition, lamellar body formation is impaired, which causes abnormal processing of SP-B and SP-C. ABCA3 gene mutations result in abnormal surfactant composition and function. It has been suggested that mutations that eliminate ABCA3 protein function cause severe forms of surfactant dysfunction, and mutations that leave some residual ABCA3 activity cause milder forms of the condition. | surfactant dysfunction |
Is surfactant dysfunction inherited ? | Surfactant dysfunction can have different inheritance patterns depending on its genetic cause. When caused by mutations in the SFTPB or ABCA3 gene, 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. When caused by mutations in the SFTPC gene, this condition has an autosomal dominant inheritance pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In about half of cases caused by changes in the SFTPC gene, an affected person inherits the mutation from one affected parent. The remainder result from new mutations in the gene and occur in people with no history of the disorder in their family. | surfactant dysfunction |
What are the treatments for surfactant dysfunction ? | These resources address the diagnosis or management of surfactant dysfunction: - Children's Interstitial and Diffuse Lung Disease (chILD) Foundation: Surfactant Deficiency - Genetic Testing Registry: Surfactant metabolism dysfunction, pulmonary, 1 - Genetic Testing Registry: Surfactant metabolism dysfunction, pulmonary, 2 - Genetic Testing Registry: Surfactant metabolism dysfunction, pulmonary, 4 - Genetic Testing Registry: Surfactant metabolism dysfunction, pulmonary, 5 - National Heart Lung and Blood Institute: How is Respiratory Distress Syndrome Diagnosed? - National Heart Lung and Blood Institute: How is Respiratory Distress Syndrome 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 | surfactant dysfunction |
What is (are) C3 glomerulopathy ? | C3 glomerulopathy is a group of related conditions that cause the kidneys to malfunction. The major features of C3 glomerulopathy include high levels of protein in the urine (proteinuria), blood in the urine (hematuria), reduced amounts of urine, low levels of protein in the blood, and swelling in many areas of the body. Affected individuals may have particularly low levels of a protein called complement component 3 (or C3) in the blood. The kidney problems associated with C3 glomerulopathy tend to worsen over time. About half of affected individuals develop end-stage renal disease (ESRD) within 10 years after their diagnosis. ESRD is a life-threatening condition that prevents the kidneys from filtering fluids and waste products from the body effectively. Researchers have identified two major forms of C3 glomerulopathy: dense deposit disease and C3 glomerulonephritis. Although the two disorders cause similar kidney problems, the features of dense deposit disease tend to appear earlier than those of C3 glomerulonephritis, usually in adolescence. However, the signs and symptoms of either disease may not begin until adulthood. One of the two forms of C3 glomerulopathy, dense deposit disease, can also be associated with other conditions unrelated to kidney function. For example, people with dense deposit disease may have acquired partial lipodystrophy, a condition characterized by a lack of fatty (adipose) tissue under the skin in the upper part of the body. Additionally, some people with dense deposit disease develop a buildup of yellowish deposits called drusen in the light-sensitive tissue at the back of the eye (the retina). These deposits usually appear in childhood or adolescence and can cause vision problems later in life. | C3 glomerulopathy |
How many people are affected by C3 glomerulopathy ? | C3 glomerulopathy is very rare, affecting 1 to 2 per million people worldwide. It is equally common in men and women. | C3 glomerulopathy |
What are the genetic changes related to C3 glomerulopathy ? | C3 glomerulopathy is associated with changes in many genes. Most of these genes provide instructions for making proteins that help regulate a part of the body's immune response known as the complement system. This system is a group of proteins that work together to destroy foreign invaders (such as bacteria and viruses), trigger inflammation, and remove debris from cells and tissues. The complement system must be carefully regulated so it targets only unwanted materials and does not damage the body's healthy cells. A specific mutation in one of the complement system-related genes, CFHR5, has been found to cause C3 glomerulopathy in people from the Mediterranean island of Cyprus. Mutation in the C3 and CFH genes, as well as other complement system-related genes, have been found to cause the condition in other populations. The known mutations account for only a small percentage of all cases of C3 glomerulopathy. In most cases, the cause of the condition is unknown. Several normal variants (polymorphisms) in complement system-related genes are associated with an increased likelihood of developing C3 glomerulopathy. In some cases, the increased risk is related to a group of specific variants in several genes, a combination known as a C3 glomerulopathy at-risk haplotype. While these polymorphisms increase the risk of C3 glomerulopathy, many people who inherit these genetic changes will never develop the condition. The genetic changes related to C3 glomerulopathy "turn up," or increase the activation of, the complement system. The overactive system damages structures called glomeruli in the kidneys. These structures are clusters of tiny blood vessels that help filter waste products from the blood. Damage to glomeruli prevents the kidneys from filtering waste products normally and can lead to ESRD. Studies suggest that uncontrolled activation of the complement system also causes the other health problems that can occur with dense deposit disease, including acquired partial lipodystrophy and a buildup of drusen in the retina. Researchers are working to determine how these associated health problems are related to overactivity of the complement system. Studies suggest that C3 glomerulopathy can also result from the presence of specialized proteins called autoantibodies. Autoantibodies cause the condition by altering the activity of proteins involved in regulating the complement system. | C3 glomerulopathy |
Is C3 glomerulopathy inherited ? | Most cases of C3 glomerulopathy are sporadic, which means they occur in people with no history of the disorder in their family. Only a few reported families have had more than one family member with C3 glomerulopathy. However, many affected people have had close relatives with autoimmune diseases, which occur when the immune system malfunctions and attacks the body's tissues and organs. The connection between C3 glomerulopathy and autoimmune diseases is not fully understood. | C3 glomerulopathy |
What are the treatments for C3 glomerulopathy ? | These resources address the diagnosis or management of C3 glomerulopathy: - Gene Review: Gene Review: Dense Deposit Disease / Membranoproliferative Glomerulonephritis Type II - Genetic Testing Registry: C3 Glomerulonephritis - Genetic Testing Registry: CFHR5 deficiency - Genetic Testing Registry: CFHR5-Related Dense Deposit Disease / Membranoproliferative Glomerulonephritis Type II - Genetic Testing Registry: Factor H deficiency - Genetic Testing Registry: Mesangiocapillary glomerulonephritis, type II - National Institute of Diabetes and Digestive and Kidney Diseases: Kidney Failure: Choosing a Treatment That's Right for You 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 | C3 glomerulopathy |
What is (are) sepiapterin reductase deficiency ? | Sepiapterin reductase deficiency is a condition characterized by movement problems, most often a pattern of involuntary, sustained muscle contractions known as dystonia. Other movement problems can include muscle stiffness (spasticity), tremors, problems with coordination and balance (ataxia), and involuntary jerking movements (chorea). People with sepiapterin reductase deficiency can experience episodes called oculogyric crises. These episodes involve abnormal rotation of the eyeballs; extreme irritability and agitation; and pain, muscle spasms, and uncontrolled movements, especially of the head and neck. Movement abnormalities are often worse late in the day. Most affected individuals have delayed development of motor skills such as sitting and crawling, and they typically are not able to walk unassisted. The problems with movement tend to worsen over time. People with sepiapterin reductase deficiency may have additional signs and symptoms including an unusually small head size (microcephaly), intellectual disability, seizures, excessive sleeping, and mood swings. | sepiapterin reductase deficiency |
How many people are affected by sepiapterin reductase deficiency ? | Sepiapterin reductase deficiency appears to be a rare condition. At least 30 cases have been described in the scientific literature. | sepiapterin reductase deficiency |
What are the genetic changes related to sepiapterin reductase deficiency ? | Mutations in the SPR gene cause sepiapterin reductase deficiency. The SPR gene provides instructions for making the sepiapterin reductase enzyme. This enzyme is involved in the production of a molecule called tetrahydrobiopterin (also known as BH4). Specifically, sepiapterin reductase is responsible for the last step in the production of tetrahydrobiopterin. Tetrahydrobiopterin helps process several building blocks of proteins (amino acids), and is involved in the production of chemicals called neurotransmitters, which transmit signals between nerve cells in the brain. SPR gene mutations disrupt the production of sepiapterin reductase. Most SPR gene mutations result in an enzyme with little or no function. A nonfunctional sepiapterin reductase leads to a lack of tetrahydrobiopterin. In most parts of the body, there are alternate pathways that do not use sepiapterin reductase for the production of tetrahydrobiopterin, but these pathways are not found in the brain. Therefore, people with sepiapterin reductase deficiency have a lack of tetrahydrobiopterin in the brain. When no tetrahydrobiopterin is produced in the brain, production of dopamine and serotonin is greatly reduced. Among their many functions, dopamine transmits signals within the brain to produce smooth physical movements, and serotonin regulates mood, emotion, sleep, and appetite. The lack of these two neurotransmitters causes the problems with movement and other features of sepiapterin reductase deficiency. | sepiapterin reductase deficiency |
Is sepiapterin reductase 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. | sepiapterin reductase deficiency |
What are the treatments for sepiapterin reductase deficiency ? | These resources address the diagnosis or management of sepiapterin reductase deficiency: - Gene Review: Gene Review: Sepiapterin Reductase Deficiency - Genetic Testing Registry: Sepiapterin reductase 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 | sepiapterin reductase deficiency |
What is (are) familial adenomatous polyposis ? | Familial adenomatous polyposis (FAP) is an inherited disorder characterized by cancer of the large intestine (colon) and rectum. People with the classic type of familial adenomatous polyposis may begin to develop multiple noncancerous (benign) growths (polyps) in the colon as early as their teenage years. Unless the colon is removed, these polyps will become malignant (cancerous). The average age at which an individual develops colon cancer in classic familial adenomatous polyposis is 39 years. Some people have a variant of the disorder, called attenuated familial adenomatous polyposis, in which polyp growth is delayed. The average age of colorectal cancer onset for attenuated familial adenomatous polyposis is 55 years. In people with classic familial adenomatous polyposis, the number of polyps increases with age, and hundreds to thousands of polyps can develop in the colon. Also of particular significance are noncancerous growths called desmoid tumors. These fibrous tumors usually occur in the tissue covering the intestines and may be provoked by surgery to remove the colon. Desmoid tumors tend to recur after they are surgically removed. In both classic familial adenomatous polyposis and its attenuated variant, benign and malignant tumors are sometimes found in other places in the body, including the duodenum (a section of the small intestine), stomach, bones, skin, and other tissues. People who have colon polyps as well as growths outside the colon are sometimes described as having Gardner syndrome. A milder type of familial adenomatous polyposis, called autosomal recessive familial adenomatous polyposis, has also been identified. People with the autosomal recessive type of this disorder have fewer polyps than those with the classic type. Fewer than 100 polyps typically develop, rather than hundreds or thousands. The autosomal recessive type of this disorder is caused by mutations in a different gene than the classic and attenuated types of familial adenomatous polyposis. | familial adenomatous polyposis |
How many people are affected by familial adenomatous polyposis ? | The reported incidence of familial adenomatous polyposis varies from 1 in 7,000 to 1 in 22,000 individuals. | familial adenomatous polyposis |
What are the genetic changes related to familial adenomatous polyposis ? | Mutations in the APC gene cause both classic and attenuated familial adenomatous polyposis. These mutations affect the ability of the cell to maintain normal growth and function. Cell overgrowth resulting from mutations in the APC gene leads to the colon polyps seen in familial adenomatous polyposis. Although most people with mutations in the APC gene will develop colorectal cancer, the number of polyps and the time frame in which they become malignant depend on the location of the mutation in the gene. Mutations in the MUTYH gene cause autosomal recessive familial adenomatous polyposis (also called MYH-associated polyposis). Mutations in this gene prevent cells from correcting mistakes that are made when DNA is copied (DNA replication) in preparation for cell division. As these mistakes build up in a person's DNA, the likelihood of cell overgrowth increases, leading to colon polyps and the possibility of colon cancer. | familial adenomatous polyposis |
Is familial adenomatous polyposis inherited ? | Familial adenomatous polyposis can have different inheritance patterns. When familial adenomatous polyposis results from mutations in the APC 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. In most cases, an affected person has one parent with the condition. When familial adenomatous polyposis results from mutations in the MUTYH gene, it is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition. | familial adenomatous polyposis |
What are the treatments for familial adenomatous polyposis ? | These resources address the diagnosis or management of familial adenomatous polyposis: - American Medical Association and National Coalition for Health Professional Education in Genetics: Understand the Basics of Genetic Testing for Hereditary Colorectal Cancer - Gene Review: Gene Review: APC-Associated Polyposis Conditions - Gene Review: Gene Review: MUTYH-Associated Polyposis - GeneFacts: Familial Adenomatous Polyposis: Diagnosis - GeneFacts: Familial Adenomatous Polyposis: Management - Genetic Testing Registry: Desmoid disease, hereditary - Genetic Testing Registry: Familial adenomatous polyposis 1 - Genetic Testing Registry: Familial multiple polyposis syndrome - Genetic Testing Registry: MYH-associated polyposis - Genomics Education Programme (UK): Familial Adenomatous Polyposis - Genomics Education Programme (UK): MYH-Associated Polyposis - MedlinePlus Encyclopedia: Colon Cancer - MedlinePlus Encyclopedia: Colorectal polyps - National Cancer Institute: Genetic Testing for Hereditary Cancer Syndromes 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 | familial adenomatous polyposis |
What is (are) Lesch-Nyhan syndrome ? | Lesch-Nyhan syndrome is a condition that occurs almost exclusively in males. It is characterized by neurological and behavioral abnormalities and the overproduction of uric acid. Uric acid is a waste product of normal chemical processes and is found in blood and urine. Excess uric acid can be released from the blood and build up under the skin and cause gouty arthritis (arthritis caused by an accumulation of uric acid in the joints). Uric acid accumulation can also cause kidney and bladder stones. The nervous system and behavioral disturbances experienced by people with Lesch-Nyhan syndrome include abnormal involuntary muscle movements, such as tensing of various muscles (dystonia), jerking movements (chorea), and flailing of the limbs (ballismus). People with Lesch-Nyhan syndrome usually cannot walk, require assistance sitting, and generally use a wheelchair. Self-injury (including biting and head banging) is the most common and distinctive behavioral problem in individuals with Lesch-Nyhan syndrome. | Lesch-Nyhan syndrome |
How many people are affected by Lesch-Nyhan syndrome ? | The prevalence of Lesch-Nyhan syndrome is approximately 1 in 380,000 individuals. This condition occurs with a similar frequency in all populations. | Lesch-Nyhan syndrome |
What are the genetic changes related to Lesch-Nyhan syndrome ? | Mutations in the HPRT1 gene cause Lesch-Nyhan syndrome. The HPRT1 gene provides instructions for making an enzyme called hypoxanthine phosphoribosyltransferase 1. This enzyme is responsible for recycling purines, a type of building block of DNA and its chemical cousin RNA. Recycling purines ensures that cells have a plentiful supply of building blocks for the production of DNA and RNA. HPRT1 gene mutations that cause Lesch-Nyhan syndrome result in a severe shortage (deficiency) or complete absence of hypoxanthine phosphoribosyltransferase 1. When this enzyme is lacking, purines are broken down but not recycled, producing abnormally high levels of uric acid. For unknown reasons, a deficiency of hypoxanthine phosphoribosyltransferase 1 is associated with low levels of a chemical messenger in the brain called dopamine. Dopamine transmits messages that help the brain control physical movement and emotional behavior, and its shortage may play a role in the movement problems and other features of this disorder. However, it is unclear how a shortage of hypoxanthine phosphoribosyltransferase 1 causes the neurological and behavioral problems characteristic of Lesch-Nyhan syndrome. Some people with HPRT1 gene mutations produce some functional enzyme. These individuals are said to have Lesch-Nyhan variant. The signs and symptoms of Lesch-Nyhan variant are often milder than those of Lesch-Nyhan syndrome and do not include self-injury. | Lesch-Nyhan syndrome |
Is Lesch-Nyhan syndrome 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. | Lesch-Nyhan syndrome |
What are the treatments for Lesch-Nyhan syndrome ? | These resources address the diagnosis or management of Lesch-Nyhan syndrome: - Gene Review: Gene Review: Lesch-Nyhan Syndrome - Genetic Testing Registry: Lesch-Nyhan syndrome - MedlinePlus Encyclopedia: Lesch-Nyhan Syndrome - MedlinePlus Encyclopedia: Uric Acid Crystals 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 | Lesch-Nyhan syndrome |
What is (are) Warsaw breakage syndrome ? | Warsaw breakage syndrome is a condition that can cause multiple abnormalities. People with Warsaw breakage syndrome have intellectual disability that varies from mild to severe. They also have impaired growth from birth leading to short stature and a small head size (microcephaly). Affected individuals have distinctive facial features that may include a small forehead, a short nose, a small lower jaw, a flat area between the nose and mouth (philtrum), and prominent cheeks. Other common features include hearing loss caused by nerve damage in the inner ear (sensorineural hearing loss) and heart malformations. | Warsaw breakage syndrome |
How many people are affected by Warsaw breakage syndrome ? | Warsaw breakage syndrome is a rare condition; at least four cases have been described in the medical literature. | Warsaw breakage syndrome |
What are the genetic changes related to Warsaw breakage syndrome ? | Mutations in the DDX11 gene cause Warsaw breakage syndrome. The DDX11 gene provides instructions for making an enzyme called ChlR1. This enzyme functions as a helicase. Helicases are enzymes that attach (bind) to DNA and temporarily unwind the two spiral strands (double helix) of the DNA molecule. This unwinding is necessary for copying (replicating) DNA in preparation for cell division, and for repairing damaged DNA and any mistakes that are made when DNA is copied. In addition, after DNA is copied, ChlR1 plays a role in ensuring proper separation of each chromosome during cell division. By helping repair mistakes in DNA and ensuring proper DNA replication, the ChlR1 enzyme is involved in maintaining the stability of a cell's genetic information. DDX11 gene mutations severely reduce or completely eliminate ChlR1 enzyme activity. As a result, the enzyme cannot bind to DNA and cannot unwind the DNA strands to help with DNA replication and repair. A lack of functional ChlR1 impairs cell division and leads to an accumulation of DNA damage. This DNA damage can appear as breaks in the DNA, giving the condition its name. It is unclear how these problems in DNA maintenance lead to the specific abnormalities characteristic of Warsaw breakage syndrome. | Warsaw breakage syndrome |
Is Warsaw breakage 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. | Warsaw breakage syndrome |
What are the treatments for Warsaw breakage syndrome ? | These resources address the diagnosis or management of Warsaw breakage syndrome: - Centers for Disease Control and Prevention: Hearing Loss in Children - Genetic Testing Registry: Warsaw breakage syndrome - MedlinePlus Encyclopedia: Hearing Loss--Infants These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Warsaw breakage syndrome |
What is (are) autosomal recessive hyper-IgE syndrome ? | Autosomal recessive hyper-IgE syndrome (AR-HIES) is a disorder of the immune system. A hallmark feature of the condition is recurrent infections that are severe and can be life-threatening. Skin infections can be caused by bacteria, viruses, or fungi. These infections cause rashes, blisters, accumulations of pus (abscesses), open sores, and scaling. People with AR-HIES also tend to have frequent bouts of pneumonia and other respiratory tract infections. Other immune system-related problems in people with AR-HIES include an inflammatory skin disorder called eczema, food or environmental allergies, and asthma. In some affected individuals, the immune system malfunctions and attacks the body's own tissues and organs, causing autoimmune disease. For example, autoimmunity can lead to abnormal destruction of red blood cells (hemolytic anemia) in people with AR-HIES. AR-HIES is characterized by abnormally high levels of an immune system protein called immunoglobulin E (IgE) in the blood; the levels are more than 10 times higher than normal. IgE normally triggers an immune response against foreign invaders in the body, particularly parasitic worms, and plays a role in allergies. It is unclear why people with AR-HIES have such high levels of this protein. People with AR-HIES also have highly elevated numbers of certain white blood cells called eosinophils (hypereosinophilia). Eosinophils aid in the immune response and are involved in allergic reactions. Some people with AR-HIES have neurological problems, such as paralysis that affects the face or one side of the body (hemiplegia). Blockage of blood flow in the brain or abnormal bleeding in the brain, both of which can lead to stroke, can also occur in AR-HIES. People with AR-HIES have a greater-than-average risk of developing cancer, particularly cancers of the blood or skin. | autosomal recessive hyper-IgE syndrome |
How many people are affected by autosomal recessive hyper-IgE syndrome ? | AR-HIES is a rare disorder whose prevalence is unknown. | autosomal recessive hyper-IgE syndrome |
What are the genetic changes related to autosomal recessive hyper-IgE syndrome ? | AR-HIES is usually caused by mutations in the DOCK8 gene. The protein produced from this gene plays a critical role in the survival and function of several types of immune system cells. One of the protein's functions is to help maintain the structure and integrity of immune cells called T cells and NK cells, which recognize and attack foreign invaders, particularly as these cells travel to sites of infection within the body. In addition, DOCK8 is involved in chemical signaling pathways that stimulate other immune cells called B cells to mature and produce antibodies, which are specialized proteins that attach to foreign particles and germs, marking them for destruction. DOCK8 gene mutations result in the production of little or no functional DOCK8 protein. Shortage of this protein impairs normal immune cell development and function. It is thought that T cells and NK cells lacking DOCK8 cannot maintain their shape as they move through dense spaces, such as those found within the skin. The abnormal cells die, resulting in reduced numbers of these cells. A shortage of these immune cells impairs the immune response to foreign invaders, accounting for the severe viral skin infections common in AR-HIES. A lack of DOCK8 also impairs B cell maturation and the production of antibodies. A lack of this type of immune response leads to recurrent respiratory tract infections in people with this disorder. It is unclear how DOCK8 gene mutations are involved in other features of AR-HIES, such as the elevation of IgE levels, autoimmunity, and neurological problems. Some people with AR-HIES do not have mutations in the DOCK8 gene. The genetic cause of the condition in these individuals is unknown. | autosomal recessive hyper-IgE syndrome |
Is autosomal recessive hyper-IgE 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. | autosomal recessive hyper-IgE syndrome |
What are the treatments for autosomal recessive hyper-IgE syndrome ? | These resources address the diagnosis or management of autosomal recessive hyper-IgE syndrome: - Genetic Testing Registry: Hyperimmunoglobulin E syndrome - MedlinePlus Encyclopedia: Hyperimmunoglobulin E Syndrome - Merck Manual Professional Version: Hyperimmunoglobulin E Syndrome - PID UK: Hyperimmunoglobulin E Syndromes Treatment and Immunizations 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 | autosomal recessive hyper-IgE syndrome |
What is (are) giant congenital melanocytic nevus ? | Giant congenital melanocytic nevus is a skin condition characterized by an abnormally dark, noncancerous skin patch (nevus) that is composed of pigment-producing cells called melanocytes. It is present from birth (congenital) or is noticeable soon after birth. The nevus may be small in infants, but it will usually grow at the same rate the body grows and will eventually be at least 40 cm (15.75 inches) across. The nevus can appear anywhere on the body, but it is more often found on the trunk or limbs. The color ranges from tan to black and can become darker or lighter over time. The surface of a nevus can be flat, rough, raised, thickened, or bumpy; the surface can vary in different regions of the nevus, and it can change over time. The skin of the nevus is often dry and prone to irritation and itching (dermatitis). Excessive hair growth (hypertrichosis) can occur within the nevus. There is often less fat tissue under the skin of the nevus; the skin may appear thinner there than over other areas of the body. People with giant congenital melanocytic nevus may have more than one nevus (plural: nevi). The other nevi are often smaller than the giant nevus. Affected individuals may have one or two additional nevi or multiple small nevi that are scattered over the skin; these are known as satellite or disseminated nevi. Affected individuals may feel anxiety or emotional stress due to the impact the nevus may have on their appearance and their health. Children with giant congenital melanocytic nevus can develop emotional or behavior problems. Some people with giant congenital melanocytic nevus develop a condition called neurocutaneous melanosis, which is the presence of pigment-producing skin cells (melanocytes) in the tissue that covers the brain and spinal cord. These melanocytes may be spread out or grouped together in clusters. Their growth can cause increased pressure in the brain, leading to headache, vomiting, irritability, seizures, and movement problems. Tumors in the brain may also develop. Individuals with giant congenital melanocytic nevus have an increased risk of developing an aggressive form of cancer called melanoma, which arises from melanocytes. Estimates vary, but it is generally thought that people with giant congenital melanocytic nevus have a 5 to 10 percent lifetime risk of developing melanoma. Melanoma commonly begins in the nevus, but it can develop when melanocytes that invade other tissues, such as those in the brain and spinal cord, become cancerous. When melanoma occurs in people with giant congenital melanocytic nevus, the survival rate is low. Other types of tumors can also develop in individuals with giant congenital melanocytic nevus, including soft tissue tumors (sarcomas), fatty tumors (lipomas), and tumors of the nerve cells (schwannomas). | giant congenital melanocytic nevus |
How many people are affected by giant congenital melanocytic nevus ? | Giant congenital melanocytic nevus occurs in approximately 1 in 20,000 newborns worldwide. | giant congenital melanocytic nevus |
What are the genetic changes related to giant congenital melanocytic nevus ? | NRAS gene mutations cause most cases of giant congenital melanocytic nevus. Rarely, mutations in the BRAF gene are responsible for this condition. The proteins produced from these genes are involved in a process known as signal transduction by which signals are relayed from outside the cell to the cell's nucleus. Signals relayed by the N-Ras and BRAF proteins instruct the cell to grow and divide (proliferate) or to mature and take on specialized functions (differentiate). To transmit signals, these proteins must be turned on; when the proteins are turned off, they do not relay signals to the cell's nucleus. The NRAS or BRAF gene mutations responsible for giant congenital melanocytic nevus are somatic, meaning that they are acquired during a person's lifetime and are present only in certain cells. These mutations occur early in embryonic development during the growth and division (proliferation) of cells that develop into melanocytes. Somatic NRAS or BRAF gene mutations cause the altered protein in affected cells to be constantly turned on (constitutively active) and relaying signals. The overactive protein may contribute to the development of giant congenital melanocytic nevus by allowing cells that develop into melanocytes to grow and divide uncontrollably, starting before birth. | giant congenital melanocytic nevus |
Is giant congenital melanocytic nevus inherited ? | This condition is generally not inherited but arises from a mutation in the body's cells that occurs after conception. This alteration is called a somatic mutation. A somatic mutation in one copy of the NRAS or BRAF gene is sufficient to cause this disorder. | giant congenital melanocytic nevus |
What are the treatments for giant congenital melanocytic nevus ? | These resources address the diagnosis or management of giant congenital melanocytic nevus: - Cleveland Clinic: The Facts About Melanoma - Genetic Testing Registry: Giant pigmented hairy nevus - MedlinePlus Encyclopedia: Giant Congenital Nevus - Nevus Outreach: Treatment Options - Primary Care Dermatology Society 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 | giant congenital melanocytic nevus |
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