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genetic changes | What are the genetic changes related to Nijmegen breakage syndrome ? | Mutations in the NBN gene cause Nijmegen breakage syndrome. The NBN gene provides instructions for making a protein called nibrin. This protein is involved in several critical cellular functions, including the repair of damaged DNA. Nibrin interacts with two other proteins as part of a larger protein complex. This protein complex works to mend broken strands of DNA. DNA can be damaged by agents such as toxic chemicals or radiation. Breaks in DNA strands also occur naturally when chromosomes exchange genetic material in preparation for cell division. Repairing DNA prevents cells from accumulating genetic damage that can cause them to die or to divide uncontrollably. The nibrin protein and the proteins with which it interacts help maintain the stability of a cell's genetic information through its roles in repairing damaged DNA and regulating cell division. The NBN gene mutations that cause this condition typically lead to the production of an abnormally short version of the nibrin protein. The defective protein is missing important regions, preventing it from responding to DNA damage effectively. As a result, affected individuals are sensitive to the effects of radiation exposure and other agents that can cause breaks in DNA. Nijmegen breakage syndrome gets its name from numerous breaks in DNA that occur in affected people's cells. A buildup of mistakes in DNA can trigger cells to grow and divide abnormally, increasing the risk of cancer in people with Nijmegen breakage syndrome. Nibrin's role in regulating cell division and cell growth (proliferation) is thought to lead to the immunodeficiency seen in affected individuals. A lack of functional nibrin results in less immune cell proliferation. A decrease in the amount of immune cells that are produced leads to reduced amounts of immunoglobulins and other features of immunodeficiency. It is unclear how mutations in the NBN gene cause the other features of Nijmegen breakage syndrome. |
inheritance | Is Nijmegen 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. |
treatment | What are the treatments for Nijmegen breakage syndrome ? | These resources address the diagnosis or management of Nijmegen breakage syndrome: - Boston Children's Hospital: Pneumonia in Children - Boston Children's Hospital: Sinusitis in Children - Cleveland Clinic: Bronchitis - Gene Review: Gene Review: Nijmegen Breakage Syndrome - Genetic Testing Registry: Microcephaly, normal intelligence and immunodeficiency These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) congenital stromal corneal dystrophy ? | Congenital stromal corneal dystrophy is an inherited eye disorder. This condition primarily affects the cornea, which is the clear outer covering of the eye. In people with this condition, the cornea appears cloudy and may have an irregular surface. These corneal changes lead to visual impairment, including blurring, glare, and a loss of sharp vision (reduced visual acuity). Visual impairment is often associated with additional eye abnormalities, including "lazy eye" (amblyopia), eyes that do not look in the same direction (strabismus), involuntary eye movements (nystagmus), and increased sensitivity to light (photophobia). |
frequency | How many people are affected by congenital stromal corneal dystrophy ? | Congenital stromal corneal dystrophy is probably very rare; only a few affected families have been reported in the medical literature. |
genetic changes | What are the genetic changes related to congenital stromal corneal dystrophy ? | Congenital stromal corneal dystrophy is caused by mutations in the DCN gene. This gene provides instructions for making a protein called decorin, which is involved in the organization of collagens. Collagens are proteins that strengthen and support connective tissues such as skin, bone, tendons, and ligaments. In the cornea, well-organized bundles of collagen make the cornea transparent. Decorin ensures that collagen fibrils in the cornea are uniformly sized and regularly spaced. Mutations in the DCN gene lead to the production of a defective version of decorin. This abnormal protein interferes with the organization of collagen fibrils in the cornea. As poorly arranged collagen fibrils accumulate, the cornea becomes cloudy. These corneal changes lead to reduced visual acuity and related eye abnormalities. |
inheritance | Is congenital stromal corneal dystrophy inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. |
treatment | What are the treatments for congenital stromal corneal dystrophy ? | These resources address the diagnosis or management of congenital stromal corneal dystrophy: - Gene Review: Gene Review: Congenital Stromal Corneal Dystrophy - Genetic Testing Registry: Congenital Stromal Corneal Dystrophy - MedlinePlus Encyclopedia: Cloudy Cornea These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Beare-Stevenson cutis gyrata syndrome ? | Beare-Stevenson cutis gyrata syndrome is a genetic disorder characterized by skin abnormalities and the premature fusion of certain bones of the skull (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face. Many of the characteristic facial features of Beare-Stevenson cutis gyrata syndrome result from the premature fusion of the skull bones. The head is unable to grow normally, which leads to a cloverleaf-shaped skull, wide-set and bulging eyes, ear abnormalities, and an underdeveloped upper jaw. Early fusion of the skull bones also affects the growth of the brain, causing delayed development and intellectual disability. A skin abnormality called cutis gyrata is also characteristic of this disorder. The skin has a furrowed and wrinkled appearance, particularly on the face, near the ears, and on the palms and soles of the feet. Additionally, thick, dark, velvety areas of skin (acanthosis nigricans) are sometimes found on the hands and feet and in the genital region. Additional signs and symptoms of Beare-Stevenson cutis gyrata syndrome can include a blockage of the nasal passages (choanal atresia), overgrowth of the umbilical stump (tissue that normally falls off shortly after birth, leaving the belly button), and abnormalities of the genitalia and anus. The medical complications associated with this condition are often life-threatening in infancy or early childhood. |
frequency | How many people are affected by Beare-Stevenson cutis gyrata syndrome ? | Beare-Stevenson cutis gyrata syndrome is a rare genetic disorder; its incidence is unknown. Fewer than 20 people with this condition have been reported worldwide. |
genetic changes | What are the genetic changes related to Beare-Stevenson cutis gyrata syndrome ? | Mutations in the FGFR2 gene cause Beare-Stevenson cutis gyrata syndrome. This gene produces a protein called fibroblast growth factor receptor 2, which plays an important role in signaling a cell to respond to its environment, perhaps by dividing or maturing. A mutation in the FGFR2 gene alters the protein and promotes prolonged signaling, which is thought to interfere with skeletal and skin development. Some individuals with Beare-Stevenson cutis gyrata syndrome do not have identified mutations in the FGFR2 gene. In these cases, the cause of the condition is unknown. |
inheritance | Is Beare-Stevenson cutis gyrata syndrome inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. All reported cases have resulted from new mutations in the gene, and occurred in people with no history of the disorder in their family. |
treatment | What are the treatments for Beare-Stevenson cutis gyrata syndrome ? | These resources address the diagnosis or management of Beare-Stevenson cutis gyrata syndrome: - Gene Review: Gene Review: FGFR-Related Craniosynostosis Syndromes - Genetic Testing Registry: Cutis Gyrata syndrome of Beare and Stevenson - MedlinePlus Encyclopedia: Acanthosis Nigricans - MedlinePlus Encyclopedia: Craniosynostosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) porphyria ? | Porphyria is a group of disorders caused by abnormalities in the chemical steps that lead to heme production. Heme is a vital molecule for all of the body's organs, although it is most abundant in the blood, bone marrow, and liver. Heme is a component of several iron-containing proteins called hemoproteins, including hemoglobin (the protein that carries oxygen in the blood). Researchers have identified several types of porphyria, which are distinguished by their genetic cause and their signs and symptoms. Some types of porphyria, called cutaneous porphyrias, primarily affect the skin. Areas of skin exposed to the sun become fragile and blistered, which can lead to infection, scarring, changes in skin coloring (pigmentation), and increased hair growth. Cutaneous porphyrias include congenital erythropoietic porphyria, erythropoietic protoporphyria, hepatoerythropoietic porphyria, and porphyria cutanea tarda. Other types of porphyria, called acute porphyrias, primarily affect the nervous system. These disorders are described as "acute" because their signs and symptoms appear quickly and usually last a short time. Episodes of acute porphyria can cause abdominal pain, vomiting, constipation, and diarrhea. During an episode, a person may also experience muscle weakness, seizures, fever, and mental changes such as anxiety and hallucinations. These signs and symptoms can be life-threatening, especially if the muscles that control breathing become paralyzed. Acute porphyrias include acute intermittent porphyria and ALAD deficiency porphyria. Two other forms of porphyria, hereditary coproporphyria and variegate porphyria, can have both acute and cutaneous symptoms. The porphyrias can also be split into erythropoietic and hepatic types, depending on where damaging compounds called porphyrins and porphyrin precursors first build up in the body. In erythropoietic porphyrias, these compounds originate in the bone marrow. Erythropoietic porphyrias include erythropoietic protoporphyria and congenital erythropoietic porphyria. Health problems associated with erythropoietic porphyrias include a low number of red blood cells (anemia) and enlargement of the spleen (splenomegaly). The other types of porphyrias are considered hepatic porphyrias. In these disorders, porphyrins and porphyrin precursors originate primarily in the liver, leading to abnormal liver function and an increased risk of developing liver cancer. Environmental factors can strongly influence the occurrence and severity of signs and symptoms of porphyria. Alcohol, smoking, certain drugs, hormones, other illnesses, stress, and dieting or periods without food (fasting) can all trigger the signs and symptoms of some forms of the disorder. Additionally, exposure to sunlight worsens the skin damage in people with cutaneous porphyrias. |
frequency | How many people are affected by porphyria ? | The exact prevalence of porphyria is unknown, but it probably ranges from 1 in 500 to 1 in 50,000 people worldwide. Overall, porphyria cutanea tarda is the most common type of porphyria. For some forms of porphyria, the prevalence is unknown because many people with a genetic mutation associated with the disease never experience signs or symptoms. Acute intermittent porphyria is the most common form of acute porphyria in most countries. It may occur more frequently in northern European countries, such as Sweden, and in the United Kingdom. Another form of the disorder, hereditary coproporphyria, has been reported mostly in Europe and North America. Variegate porphyria is most common in the Afrikaner population of South Africa; about 3 in 1,000 people in this population have the genetic change that causes this form of the disorder. |
genetic changes | What are the genetic changes related to porphyria ? | Each form of porphyria results from mutations in one of these genes: ALAD, ALAS2, CPOX, FECH, HMBS, PPOX, UROD, or UROS. The genes related to porphyria provide instructions for making the enzymes needed to produce heme. Mutations in most of these genes reduce enzyme activity, which limits the amount of heme the body can produce. As a result, compounds called porphyrins and porphyrin precursors, which are formed during the process of heme production, can build up abnormally in the liver and other organs. When these substances accumulate in the skin and interact with sunlight, they cause the cutaneous forms of porphyria. The acute forms of the disease occur when porphyrins and porphyrin precursors build up in and damage the nervous system. One type of porphyria, porphyria cutanea tarda, results from both genetic and nongenetic factors. About 20 percent of cases are related to mutations in the UROD gene. The remaining cases are not associated with UROD gene mutations and are classified as sporadic. Many factors contribute to the development of porphyria cutanea tarda. These include an increased amount of iron in the liver, alcohol consumption, smoking, hepatitis C or HIV infection, or certain hormones. Mutations in the HFE gene (which cause an iron overload disorder called hemochromatosis) are also associated with porphyria cutanea tarda. Other, as-yet-unidentified genetic factors may also play a role in this form of porphyria. |
inheritance | Is porphyria inherited ? | Some types of porphyria are inherited in an autosomal dominant pattern, which means one copy of the gene in each cell is mutated. This single mutation is sufficient to reduce the activity of an enzyme needed for heme production, which increases the risk of developing signs and symptoms of porphyria. Autosomal dominant porphyrias include acute intermittent porphyria, most cases of erythropoietic protoporphyria, hereditary coproporphyria, and variegate porphyria. Although the gene mutations associated with some cases of porphyria cutanea tarda also have an autosomal dominant inheritance pattern, most people with this form of porphyria do not have an inherited gene mutation. Other porphyrias are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition. Porphyrias with an autosomal recessive pattern of inheritance include ALAD deficiency porphyria, congenital erythropoietic porphyria, and some cases of erythropoietic protoporphyria. When erythropoietic protoporphyria is caused by mutations in the ALAS2 gene, it has an X-linked dominant pattern of inheritance. The ALAS2 gene is located on the X chromosome, which is one of the two sex chromosomes. In females (who have two X chromosomes), a mutation in one of the two copies of the gene in each cell may be sufficient to cause the disorder. In males (who have only one X chromosome), a mutation in the only copy of the gene in each cell causes the disorder. Males may experience more severe symptoms of the disorder than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. Mutations in the UROD gene are related to both porphyria cutanea tarda and hepatoerythropoietic porphyria. Individuals who inherit one altered copy of the UROD gene are at increased risk for porphyria cutanea tarda. (Multiple genetic and nongenetic factors contribute to this condition.) People who inherit two altered copies of the UROD gene in each cell develop hepatoerythropoietic porphyria. |
treatment | What are the treatments for porphyria ? | These resources address the diagnosis or management of porphyria: - Gene Review: Gene Review: Acute Intermittent Porphyria - Gene Review: Gene Review: Congenital Erythropoietic Porphyria - Gene Review: Gene Review: Erythropoietic Protoporphyria, Autosomal Recessive - Gene Review: Gene Review: Hereditary Coproporphyria - Gene Review: Gene Review: Porphyria Cutanea Tarda, Type II - Gene Review: Gene Review: Variegate Porphyria - Gene Review: Gene Review: X-Linked Protoporphyria - Genetic Testing Registry: Acute intermittent porphyria - Genetic Testing Registry: Congenital erythropoietic porphyria - Genetic Testing Registry: Erythropoietic protoporphyria - Genetic Testing Registry: Familial porphyria cutanea tarda - Genetic Testing Registry: Hereditary coproporphyria - Genetic Testing Registry: Porphyria - Genetic Testing Registry: Protoporphyria, erythropoietic, X-linked - Genetic Testing Registry: Variegate porphyria - MedlinePlus Encyclopedia: Porphyria - MedlinePlus Encyclopedia: Porphyria cutanea tarda on the hands - MedlinePlus Encyclopedia: Porphyrins - Blood - MedlinePlus Encyclopedia: Porphyrins - Urine These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) isodicentric chromosome 15 syndrome ? | Isodicentric chromosome 15 syndrome is a developmental disorder with a broad spectrum of features. The signs and symptoms vary among affected individuals. Poor muscle tone is commonly seen in individuals with isodicentric chromosome 15 syndrome and contributes to delayed development and impairment of motor skills, including sitting and walking. Babies with isodicentric chromosome 15 syndrome often have trouble feeding due to weak facial muscles that impair sucking and swallowing; many also have backflow of acidic stomach contents into the esophagus (gastroesophageal reflux). These feeding problems may make it difficult for them to gain weight. Intellectual disability in isodicentric chromosome 15 syndrome can range from mild to profound. Speech is usually delayed and often remains absent or impaired. Behavioral difficulties often associated with isodicentric chromosome 15 syndrome include hyperactivity, anxiety, and frustration leading to tantrums. Other behaviors resemble features of autistic spectrum disorders, such as repeating the words of others (echolalia), difficulty with changes in routine, and problems with social interaction. About two-thirds of people with isodicentric chromosome 15 syndrome have seizures. In more than half of affected individuals, the seizures begin in the first year of life. About 40 percent of individuals with isodicentric chromosome 15 syndrome are born with eyes that do not look in the same direction (strabismus). Hearing loss in childhood is common and is usually caused by fluid buildup in the middle ear. This hearing loss is often temporary. However, if left untreated during early childhood, the hearing loss can interfere with language development and worsen the speech problems associated with this disorder. Other problems associated with isodicentric chromosome 15 syndrome in some affected individuals include minor genital abnormalities in males such as undescended testes (cryptorchidism) and a spine that curves to the side (scoliosis). |
frequency | How many people are affected by isodicentric chromosome 15 syndrome ? | Isodicentric chromosome 15 syndrome occurs in about 1 in 30,000 newborns. |
genetic changes | What are the genetic changes related to isodicentric chromosome 15 syndrome ? | Isodicentric chromosome 15 syndrome results from the presence of an abnormal extra chromosome, called an isodicentric chromosome 15, in each cell. An isodicentric chromosome contains mirror-image segments of genetic material and has two constriction points (centromeres), rather than one centromere as in normal chromosomes. In isodicentric chromosome 15 syndrome, the isodicentric chromosome is made up of two extra copies of a segment of genetic material from chromosome 15, attached end-to-end. Typically this copied genetic material includes a region of the chromosome called 15q11-q13. Cells normally have two copies of each chromosome, one inherited from each parent. In people with isodicentric chromosome 15 syndrome, cells have the usual two copies of chromosome 15 plus the two extra copies of the segment of genetic material in the isodicentric chromosome. The extra genetic material disrupts the normal course of development, causing the characteristic features of this disorder. Some individuals with isodicentric chromosome 15 whose copied genetic material does not include the 15q11-q13 region do not show signs or symptoms of the condition. |
inheritance | Is isodicentric chromosome 15 syndrome inherited ? | Isodicentric chromosome 15 syndrome is usually not inherited. The chromosomal change that causes the disorder typically occurs as a random event during the formation of reproductive cells (eggs or sperm) in a parent of the affected individual. Most affected individuals have no history of the disorder in their family. |
treatment | What are the treatments for isodicentric chromosome 15 syndrome ? | These resources address the diagnosis or management of isodicentric chromosome 15 syndrome: - Autism Speaks: How is Autism Treated? These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) polymicrogyria ? | Polymicrogyria is a condition characterized by abnormal development of the brain before birth. The surface of the brain normally has many ridges or folds, called gyri. In people with polymicrogyria, the brain develops too many folds, and the folds are unusually small. The name of this condition literally means too many (poly-) small (micro-) folds (-gyria) in the surface of the brain. Polymicrogyria can affect part of the brain or the whole brain. When the condition affects one side of the brain, researchers describe it as unilateral. When it affects both sides of the brain, it is described as bilateral. The signs and symptoms associated with polymicrogyria depend on how much of the brain, and which particular brain regions, are affected. Researchers have identified multiple forms of polymicrogyria. The mildest form is known as unilateral focal polymicrogyria. This form of the condition affects a relatively small area on one side of the brain. It may cause minor neurological problems, such as mild seizures that can be easily controlled with medication. Some people with unilateral focal polymicrogyria do not have any problems associated with the condition. Bilateral forms of polymicrogyria tend to cause more severe neurological problems. Signs and symptoms of these conditions can include recurrent seizures (epilepsy), delayed development, crossed eyes, problems with speech and swallowing, and muscle weakness or paralysis. The most severe form of the disorder, bilateral generalized polymicrogyria, affects the entire brain. This condition causes severe intellectual disability, problems with movement, and seizures that are difficult or impossible to control with medication. Polymicrogyria most often occurs as an isolated feature, although it can occur with other brain abnormalities. It is also a feature of several genetic syndromes characterized by intellectual disability and multiple birth defects. These include 22q11.2 deletion syndrome, Adams-Oliver syndrome, Aicardi syndrome, Galloway-Mowat syndrome, Joubert syndrome, and Zellweger spectrum disorder. |
frequency | How many people are affected by polymicrogyria ? | The prevalence of isolated polymicrogyria is unknown. Researchers believe that it may be relatively common overall, although the individual forms of the disorder (such as bilateral generalized polymicrogyria) are probably rare. |
genetic changes | What are the genetic changes related to polymicrogyria ? | In most people with polymicrogyria, the cause of the condition is unknown. However, researchers have identified several environmental and genetic factors that can be responsible for the disorder. Environmental causes of polymicrogyria include certain infections during pregnancy and a lack of oxygen to the fetus (intrauterine ischemia). Researchers are investigating the genetic causes of polymicrogyria. The condition can result from deletions or rearrangements of genetic material from several different chromosomes. Additionally, mutations in one gene, ADGRG1, have been found to cause a severe form of the condition called bilateral frontoparietal polymicrogyria (BFPP). The ADGRG1 gene appears to be critical for the normal development of the outer layer of the brain. Researchers believe that many other genes are probably involved in the different forms of polymicrogyria. |
inheritance | Is polymicrogyria inherited ? | Isolated polymicrogyria can have different inheritance patterns. Several forms of the condition, including bilateral frontoparietal polymicrogyria (which is associated with mutations in the ADGRG1 gene), have an autosomal recessive pattern of inheritance. In autosomal recessive inheritance, 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. Polymicrogyria can also have an autosomal dominant inheritance pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Other forms of polymicrogyria appear to have an X-linked pattern of inheritance. Genes associated with X-linked conditions are located on the X chromosome, which is one of the two sex chromosomes. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. Some people with polymicrogyria have relatives with the disorder, while other affected individuals have no family history of the condition. When an individual is the only affected person in his or her family, it can be difficult to determine the cause and possible inheritance pattern of the disorder. |
treatment | What are the treatments for polymicrogyria ? | These resources address the diagnosis or management of polymicrogyria: - Gene Review: Gene Review: Polymicrogyria Overview - Genetic Testing Registry: Congenital bilateral perisylvian syndrome - Genetic Testing Registry: Polymicrogyria, asymmetric - Genetic Testing Registry: Polymicrogyria, bilateral frontoparietal - Genetic Testing Registry: Polymicrogyria, bilateral occipital These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Pompe disease ? | Pompe disease is an inherited disorder caused by the buildup of a complex sugar called glycogen in the body's cells. The accumulation of glycogen in certain organs and tissues, especially muscles, impairs their ability to function normally. Researchers have described three types of Pompe disease, which differ in severity and the age at which they appear. These types are known as classic infantile-onset, non-classic infantile-onset, and late-onset. The classic form of infantile-onset Pompe disease begins within a few months of birth. Infants with this disorder typically experience muscle weakness (myopathy), poor muscle tone (hypotonia), an enlarged liver (hepatomegaly), and heart defects. Affected infants may also fail to gain weight and grow at the expected rate (failure to thrive) and have breathing problems. If untreated, this form of Pompe disease leads to death from heart failure in the first year of life. The non-classic form of infantile-onset Pompe disease usually appears by age 1. It is characterized by delayed motor skills (such as rolling over and sitting) and progressive muscle weakness. The heart may be abnormally large (cardiomegaly), but affected individuals usually do not experience heart failure. The muscle weakness in this disorder leads to serious breathing problems, and most children with non-classic infantile-onset Pompe disease live only into early childhood. The late-onset type of Pompe disease may not become apparent until later in childhood, adolescence, or adulthood. Late-onset Pompe disease is usually milder than the infantile-onset forms of this disorder and is less likely to involve the heart. Most individuals with late-onset Pompe disease experience progressive muscle weakness, especially in the legs and the trunk, including the muscles that control breathing. As the disorder progresses, breathing problems can lead to respiratory failure. |
frequency | How many people are affected by Pompe disease ? | Pompe disease affects about 1 in 40,000 people in the United States. The incidence of this disorder varies among different ethnic groups. |
genetic changes | What are the genetic changes related to Pompe disease ? | Mutations in the GAA gene cause Pompe disease. The GAA gene provides instructions for producing an enzyme called acid alpha-glucosidase (also known as acid maltase). This enzyme is active in lysosomes, which are structures that serve as recycling centers within cells. The enzyme normally breaks down glycogen into a simpler sugar called glucose, which is the main energy source for most cells. Mutations in the GAA gene prevent acid alpha-glucosidase from breaking down glycogen effectively, which allows this sugar to build up to toxic levels in lysosomes. This buildup damages organs and tissues throughout the body, particularly the muscles, leading to the progressive signs and symptoms of Pompe disease. |
inheritance | Is Pompe disease inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for Pompe disease ? | These resources address the diagnosis or management of Pompe disease: - Baby's First Test - Gene Review: Gene Review: Glycogen Storage Disease Type II (Pompe Disease) - Genetic Testing Registry: Glycogen storage disease type II, infantile - Genetic Testing Registry: Glycogen storage disease, type II These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) hereditary xanthinuria ? | Hereditary xanthinuria is a condition that most often affects the kidneys. It is characterized by high levels of a compound called xanthine and very low levels of another compound called uric acid in the blood and urine. The excess xanthine can accumulate in the kidneys and other tissues. In the kidneys, xanthine forms tiny crystals that occasionally build up to create kidney stones. These stones can impair kidney function and ultimately cause kidney failure. Related signs and symptoms can include abdominal pain, recurrent urinary tract infections, and blood in the urine (hematuria). Less commonly, xanthine crystals build up in the muscles, causing pain and cramping. In some people with hereditary xanthinuria, the condition does not cause any health problems. Researchers have described two major forms of hereditary xanthinuria, types I and II. The types are distinguished by the enzymes involved; they have the same signs and symptoms. |
frequency | How many people are affected by hereditary xanthinuria ? | The combined incidence of hereditary xanthinuria types I and II is estimated to be about 1 in 69,000 people worldwide. However, researchers suspect that the true incidence may be higher because some affected individuals have no symptoms and are never diagnosed with the condition. Hereditary xanthinuria appears to be more common in people of Mediterranean or Middle Eastern ancestry. About 150 cases of this condition have been reported in the medical literature. |
genetic changes | What are the genetic changes related to hereditary xanthinuria ? | Hereditary xanthinuria type I is caused by mutations in the XDH gene. This gene provides instructions for making an enzyme called xanthine dehydrogenase. This enzyme is involved in the normal breakdown of purines, which are building blocks of DNA and its chemical cousin, RNA. Specifically, xanthine dehydrogenase carries out the final two steps in the process, including the conversion of xanthine to uric acid (which is excreted in urine and feces). Mutations in the XDH gene reduce or eliminate the activity of xanthine dehydrogenase. As a result, the enzyme is not available to help carry out the last two steps of purine breakdown. Because xanthine is not converted to uric acid, affected individuals have high levels of xanthine and very low levels of uric acid in their blood and urine. The excess xanthine can cause damage to the kidneys and other tissues. Hereditary xanthinuria type II results from mutations in the MOCOS gene. This gene provides instructions for making an enzyme called molybdenum cofactor sulfurase. This enzyme is necessary for the normal function of xanthine dehydrogenase, described above, and another enzyme called aldehyde oxidase. Mutations in the MOCOS gene prevent xanthine dehydrogenase and aldehyde oxidase from being turned on (activated). The loss of xanthine dehydrogenase activity prevents the conversion of xanthine to uric acid, leading to an accumulation of xanthine in the kidneys and other tissues. The loss of aldehyde oxidase activity does not appear to cause any health problems. |
inheritance | Is hereditary xanthinuria inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for hereditary xanthinuria ? | These resources address the diagnosis or management of hereditary xanthinuria: - Genetic Testing Registry: Deficiency of xanthine oxidase - Genetic Testing Registry: Xanthinuria type 2 - MedlinePlus Encyclopedia: Uric Acid - Blood These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) hyperkalemic periodic paralysis ? | Hyperkalemic periodic paralysis is a condition that causes episodes of extreme muscle weakness or paralysis, usually beginning in infancy or early childhood. Most often, these episodes involve a temporary inability to move muscles in the arms and legs. Episodes tend to increase in frequency until mid-adulthood, after which they occur less frequently. Factors that can trigger attacks include rest after exercise, potassium-rich foods such as bananas and potatoes, stress, fatigue, alcohol, pregnancy, exposure to cold temperatures, certain medications, and periods without food (fasting). Muscle strength usually returns to normal between attacks, although many affected people continue to experience mild stiffness (myotonia), particularly in muscles of the face and hands. Most people with hyperkalemic periodic paralysis have increased levels of potassium in their blood (hyperkalemia) during attacks. Hyperkalemia results when the weak or paralyzed muscles release potassium ions into the bloodstream. In other cases, attacks are associated with normal blood potassium levels (normokalemia). Ingesting potassium can trigger attacks in affected individuals, even if blood potassium levels do not go up. |
frequency | How many people are affected by hyperkalemic periodic paralysis ? | Hyperkalemic periodic paralysis affects an estimated 1 in 200,000 people. |
genetic changes | What are the genetic changes related to hyperkalemic periodic paralysis ? | Mutations in the SCN4A gene can cause hyperkalemic periodic paralysis. The SCN4A gene provides instructions for making a protein that plays an essential role in muscles used for movement (skeletal muscles). For the body to move normally, these muscles must tense (contract) and relax in a coordinated way. One of the changes that helps trigger muscle contractions is the flow of positively charged atoms (ions), including sodium, into 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 stay open too long or do not stay closed long enough, allowing more sodium ions to flow into muscle cells. This increase in sodium ions triggers the release of potassium from muscle cells, which causes more sodium channels to open and stimulates the flow of even more sodium ions into these cells. These changes in ion transport reduce the ability of skeletal muscles to contract, leading to episodes of muscle weakness or paralysis. In 30 to 40 percent of cases, the cause of hyperkalemic periodic paralysis is unknown. Changes in other genes, which have not been identified, likely cause the disorder in these cases. |
inheritance | Is hyperkalemic periodic paralysis inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. |
treatment | What are the treatments for hyperkalemic periodic paralysis ? | These resources address the diagnosis or management of hyperkalemic periodic paralysis: - Gene Review: Gene Review: Hyperkalemic Periodic Paralysis - Genetic Testing Registry: Familial hyperkalemic periodic paralysis - Genetic Testing Registry: Hyperkalemic Periodic Paralysis Type 1 - MedlinePlus Encyclopedia: Hyperkalemic Periodic Paralysis - Periodic Paralysis International: How is Periodic Paralysis Diagnosed? These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) arginase deficiency ? | Arginase deficiency is an inherited disorder that causes the amino acid arginine (a building block of proteins) and ammonia to accumulate gradually in the blood. Ammonia, which is formed when proteins are broken down in the body, is toxic if levels become too high. The nervous system is especially sensitive to the effects of excess ammonia. Arginase deficiency usually becomes evident by about the age of 3. It most often appears as stiffness, especially in the legs, caused by abnormal tensing of the muscles (spasticity). Other symptoms may include slower than normal growth, developmental delay and eventual loss of developmental milestones, intellectual disability, seizures, tremor, and difficulty with balance and coordination (ataxia). Occasionally, high protein meals or stress caused by illness or periods without food (fasting) may cause ammonia to accumulate more quickly in the blood. This rapid increase in ammonia may lead to episodes of irritability, refusal to eat, and vomiting. In some affected individuals, signs and symptoms of arginase deficiency may be less severe, and may not appear until later in life. |
frequency | How many people are affected by arginase deficiency ? | Arginase deficiency is a very rare disorder; it has been estimated to occur once in every 300,000 to 1,000,000 individuals. |
genetic changes | What are the genetic changes related to arginase deficiency ? | Mutations in the ARG1 gene cause arginase deficiency. Arginase deficiency belongs to a class of genetic diseases called urea cycle disorders. The urea cycle is a sequence of reactions that occurs in liver cells. This cycle processes excess nitrogen, generated when protein is used by the body, to make a compound called urea that is excreted by the kidneys. The ARG1 gene provides instructions for making an enzyme called arginase. This enzyme controls the final step of the urea cycle, which produces urea by removing nitrogen from arginine. In people with arginase deficiency, arginase is damaged or missing, and arginine is not broken down properly. As a result, urea cannot be produced normally, and excess nitrogen accumulates in the blood in the form of ammonia. The accumulation of ammonia and arginine are believed to cause the neurological problems and other signs and symptoms of arginase deficiency. |
inheritance | Is arginase deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for arginase deficiency ? | These resources address the diagnosis or management of arginase deficiency: - Baby's First Test - Gene Review: Gene Review: Arginase Deficiency - Gene Review: Gene Review: Urea Cycle Disorders Overview - Genetic Testing Registry: Arginase deficiency - MedlinePlus Encyclopedia: Hereditary urea cycle abnormality These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) neuroblastoma ? | Neuroblastoma is a type of cancer that most often affects children. Neuroblastoma occurs when immature nerve cells called neuroblasts become abnormal and multiply uncontrollably to form a tumor. Most commonly, the tumor originates in the nerve tissue of the adrenal gland located above each kidney. Other common sites for tumors to form include the nerve tissue in the abdomen, chest, neck, or pelvis. Neuroblastoma can spread (metastasize) to other parts of the body such as the bones, liver, or skin. Individuals with neuroblastoma may develop general signs and symptoms such as irritability, fever, tiredness (fatigue), pain, loss of appetite, weight loss, or diarrhea. More specific signs and symptoms depend on the location of the tumor and where it has spread. A tumor in the abdomen can cause abdominal swelling. A tumor in the chest may lead to difficulty breathing. A tumor in the neck can cause nerve damage known as Horner syndrome, which leads to drooping eyelids, small pupils, decreased sweating, and red skin. Tumor metastasis to the bone can cause bone pain, bruises, pale skin, or dark circles around the eyes. Tumors in the backbone can press on the spinal cord and cause weakness, numbness, or paralysis in the arms or legs. A rash of bluish or purplish bumps that look like blueberries indicates that the neuroblastoma has spread to the skin. In addition, neuroblastoma tumors can release hormones that may cause other signs and symptoms such as high blood pressure, rapid heartbeat, flushing of the skin, and sweating. In rare instances, individuals with neuroblastoma may develop opsoclonus myoclonus syndrome, which causes rapid eye movements and jerky muscle motions. This condition occurs when the immune system malfunctions and attacks nerve tissue. Neuroblastoma occurs most often in children before age 5 and rarely occurs in adults. |
frequency | How many people are affected by neuroblastoma ? | Neuroblastoma is the most common cancer in infants younger than 1 year. It occurs in 1 in 100,000 children and is diagnosed in about 650 children each year in the United States. |
genetic changes | What are the genetic changes related to neuroblastoma ? | Neuroblastoma and other cancers occur when a buildup of genetic mutations in critical genesthose that control cell growth and division (proliferation) or maturation (differentiation)allow cells to grow and divide uncontrollably to form a tumor. In most cases, these genetic changes are acquired during a person's lifetime and are called somatic mutations. Somatic mutations are present only in certain cells and are not inherited. When neuroblastoma is associated with somatic mutations, it is called sporadic neuroblastoma. It is thought that somatic mutations in at least two genes are required to cause sporadic neuroblastoma. Less commonly, gene mutations that increase the risk of developing cancer can be inherited from a parent. When the mutation associated with neuroblastoma is inherited, the condition is called familial neuroblastoma. Mutations in the ALK and PHOX2B genes have been shown to increase the risk of developing sporadic and familial neuroblastoma. It is likely that there are other genes involved in the formation of neuroblastoma. Several mutations in the ALK gene are involved in the development of sporadic and familial neuroblastoma. The ALK gene provides instructions for making a protein called anaplastic lymphoma kinase. Although the specific function of this protein is unknown, it appears to play an important role in cell proliferation. Mutations in the ALK gene result in an abnormal version of anaplastic lymphoma kinase that is constantly turned on (constitutively activated). Constitutively active anaplastic lymphoma kinase may induce abnormal proliferation of immature nerve cells and lead to neuroblastoma. Several mutations in the PHOX2B gene have been identified in sporadic and familial neuroblastoma. The PHOX2B gene is important for the formation and differentiation of nerve cells. Mutations in this gene are believed to interfere with the PHOX2B protein's role in promoting nerve cell differentiation. This disruption of differentiation results in an excess of immature nerve cells and leads to neuroblastoma. Deletion of certain regions of chromosome 1 and chromosome 11 are associated with neuroblastoma. Researchers believe the deleted regions in these chromosomes could contain a gene that keeps cells from growing and dividing too quickly or in an uncontrolled way, called a tumor suppressor gene. When a tumor suppressor gene is deleted, cancer can occur. The KIF1B gene is a tumor suppressor gene located in the deleted region of chromosome 1, and mutations in this gene have been identified in some people with familial neuroblastoma, indicating it is involved in neuroblastoma development or progression. There are several other possible tumor suppressor genes in the deleted region of chromosome 1. No tumor suppressor genes have been identified in the deleted region of chromosome 11. Another genetic change found in neuroblastoma is associated with the severity of the disease but not thought to cause it. About 25 percent of people with neuroblastoma have extra copies of the MYCN gene, a phenomenon called gene amplification. It is unknown how amplification of this gene contributes to the aggressive nature of neuroblastoma. |
inheritance | Is neuroblastoma inherited ? | Most people with neuroblastoma have sporadic neuroblastoma, meaning the condition arose from somatic mutations in the body's cells and was not inherited. About 1 to 2 percent of affected individuals have familial neuroblastoma. This form of the condition has an autosomal dominant inheritance pattern, which means one copy of the altered gene in each cell increases the risk of developing the disorder. However, the inheritance is considered to have incomplete penetrance because not everyone who inherits the altered gene from a parent develops neuroblastoma. Having the altered gene predisposes an individual to develop neuroblastoma, but an additional somatic mutation is probably needed to cause the condition. |
treatment | What are the treatments for neuroblastoma ? | These resources address the diagnosis or management of neuroblastoma: - American Cancer Society: Diagnosis of Neuroblastoma - Gene Review: Gene Review: ALK-Related Neuroblastic Tumor Susceptibility - Genetic Testing Registry: Neuroblastoma - Genetic Testing Registry: Neuroblastoma 2 - Genetic Testing Registry: Neuroblastoma 3 - National Cancer Institute - The Children's Hospital of Pennsylvania These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Birt-Hogg-Dub syndrome ? | Birt-Hogg-Dub syndrome is a rare disorder that affects the skin and lungs and increases the risk of certain types of tumors. Its signs and symptoms vary among affected individuals. Birt-Hogg-Dub syndrome is characterized by multiple noncancerous (benign) skin tumors, particularly on the face, neck, and upper chest. These growths typically first appear in a person's twenties or thirties and become larger and more numerous over time. Affected individuals also have an increased chance of developing cysts in the lungs and an abnormal accumulation of air in the chest cavity (pneumothorax) that may result in the collapse of a lung. Additionally, Birt-Hogg-Dub syndrome is associated with an elevated risk of developing cancerous or noncancerous kidney tumors. Other types of cancer have also been reported in affected individuals, but it is unclear whether these tumors are actually a feature of Birt-Hogg-Dub syndrome. |
frequency | How many people are affected by Birt-Hogg-Dub syndrome ? | Birt-Hogg-Dub syndrome is rare; its exact incidence is unknown. This condition has been reported in more than 400 families. |
genetic changes | What are the genetic changes related to Birt-Hogg-Dub syndrome ? | Mutations in the FLCN gene cause Birt-Hogg-Dub syndrome. This gene provides instructions for making a protein called folliculin. The normal function of this protein is unknown, but researchers believe that it may act as a tumor suppressor. Tumor suppressors prevent cells from growing and dividing too rapidly or in an uncontrolled way. Mutations in the FLCN gene may interfere with the ability of folliculin to restrain cell growth and division, leading to uncontrolled cell growth and the formation of noncancerous and cancerous tumors. Researchers have not determined how FLCN mutations increase the risk of lung problems, such as pneumothorax. |
inheritance | Is Birt-Hogg-Dub syndrome inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered FLCN gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the mutation from one affected parent. Less commonly, the condition results from a new mutation in the gene and occurs in people with no history of the disorder in their family. Having a single mutated copy of the FLCN gene in each cell is enough to cause the skin tumors and lung problems associated with Birt-Hogg-Dub syndrome. However, both copies of the FLCN gene are often mutated in the kidney tumors that occur with this condition. One of the mutations is inherited from a parent, while the other occurs by chance in a kidney cell during a person's lifetime. These genetic changes disable both copies of the FLCN gene, which allows kidney cells to divide uncontrollably and form tumors. |
treatment | What are the treatments for Birt-Hogg-Dub syndrome ? | These resources address the diagnosis or management of Birt-Hogg-Dub syndrome: - BHD Foundation: Practical Considerations - Gene Review: Gene Review: Birt-Hogg-Dube Syndrome - Genetic Testing Registry: Multiple fibrofolliculomas - MedlinePlus Encyclopedia: Collapsed Lung These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) N-acetylglutamate synthase deficiency ? | N-acetylglutamate synthase deficiency is an inherited disorder that causes ammonia to accumulate in the blood. Ammonia, which is formed when proteins are broken down in the body, is toxic if the levels become too high. The nervous system is especially sensitive to the effects of excess ammonia. N-acetylglutamate synthase deficiency may become evident in the first few days of life. An infant with this condition may be lacking in energy (lethargic) or unwilling to eat, and have a poorly controlled breathing rate or body temperature. Some babies with this disorder may experience seizures or unusual body movements, or go into a coma. Complications of N-acetylglutamate synthase deficiency may include developmental delay and intellectual disability. In some affected individuals, signs and symptoms of N-acetylglutamate synthase deficiency are less severe, and do not appear until later in life. Some people with this form of the disorder cannot tolerate high-protein foods such as meat. They may experience sudden episodes of ammonia toxicity, resulting in vomiting, lack of coordination, confusion or coma, in response to illness or other stress. |
frequency | How many people are affected by N-acetylglutamate synthase deficiency ? | N-acetylglutamate synthase deficiency is a very rare disorder. Only a few cases have been reported worldwide, and the overall incidence is unknown. |
genetic changes | What are the genetic changes related to N-acetylglutamate synthase deficiency ? | Mutations in the NAGS gene cause N-acetylglutamate synthase deficiency. N-acetylglutamate synthase deficiency belongs to a class of genetic diseases called urea cycle disorders. The urea cycle is a sequence of reactions that occurs in liver cells. This cycle processes excess nitrogen, generated when protein is used by the body, to make a compound called urea that is excreted by the kidneys. The NAGS gene provides instructions for making the enzyme N-acetylglutamate synthase, which helps produce a compound called N-acetylglutamate. This compound is needed to activate another enzyme, carbamoyl phosphate synthetase I, which controls the first step of the urea cycle. In people with N-acetylglutamate synthase deficiency, N-acetylglutamate is not available in sufficient quantities, or is not present at all. As a result, urea cannot be produced normally, and excess nitrogen accumulates in the blood in the form of ammonia. This accumulation of ammonia causes the neurological problems and other signs and symptoms of N-acetylglutamate synthase deficiency. |
inheritance | Is N-acetylglutamate synthase deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for N-acetylglutamate synthase deficiency ? | These resources address the diagnosis or management of N-acetylglutamate synthase deficiency: - Gene Review: Gene Review: Urea Cycle Disorders Overview - Genetic Testing Registry: Hyperammonemia, type III - MedlinePlus Encyclopedia: Hereditary Urea Cycle Abnormality These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Winchester syndrome ? | Winchester syndrome is a rare inherited disease characterized by a loss of bone tissue (osteolysis), particularly in the hands and feet. Winchester syndrome used to be considered part of a related condition now called multicentric osteolysis, nodulosis, and arthropathy (MONA). However, because Winchester syndrome and MONA are caused by mutations in different genes, they are now thought to be separate disorders. In most cases of Winchester syndrome, bone loss begins in the hands and feet, causing pain and limiting movement. Bone abnormalities later spread to other parts of the body, with joint problems (arthropathy) occurring in the elbows, shoulders, knees, hips, and spine. Most people with Winchester syndrome develop low bone mineral density (osteopenia) and thinning of the bones (osteoporosis) throughout the skeleton. These abnormalities make bones brittle and more prone to fracture. The bone abnormalities also lead to short stature. Some people with Winchester syndrome have skin abnormalities including patches of dark, thick, and leathery skin. Other features of the condition can include clouding of the clear front covering of the eye (corneal opacity), excess hair growth (hypertrichosis), overgrowth of the gums, heart abnormalities, and distinctive facial features that are described as "coarse." |
frequency | How many people are affected by Winchester syndrome ? | Winchester syndrome is a rare condition whose prevalence is unknown. It has been reported in only a few individuals worldwide. |
genetic changes | What are the genetic changes related to Winchester syndrome ? | Winchester syndrome is caused by mutations in the MMP14 gene (also known as MT1-MMP). This gene provides instructions for making a protein called matrix metallopeptidase 14, which is found on the surface of cells. Matrix metallopeptidase 14 normally helps modify and break down various components of the extracellular matrix, which is the intricate lattice of proteins and other molecules that forms in the spaces between cells. These changes influence many cell activities and functions, including promoting cell growth and stimulating cell movement (migration). Matrix metallopeptidase 14 also turns on (activates) a protein called matrix metallopeptidase 2. The activity of matrix metallopeptidase 2 appears to be important for a variety of body functions, including bone remodeling, which is a normal process in which old bone is broken down and new bone is created to replace it. Mutations in the MMP14 gene alter matrix metallopeptidase 14 so that less of the enzyme is able to reach the cell surface. As a result, not enough of the enzyme is available to break down components of the extracellular matrix and activate matrix metallopeptidase 2. It is unclear how a shortage of this enzyme leads to the signs and symptoms of Winchester syndrome. It is possible that a loss of matrix metallopeptidase 2 activation somehow disrupts the balance of new bone creation and the breakdown of existing bone during bone remodeling, causing a progressive loss of bone tissue. How a reduced amount of matrix metallopeptidase 14 leads to the other features of Winchester syndrome is unknown. |
inheritance | Is Winchester syndrome inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for Winchester syndrome ? | These resources address the diagnosis or management of Winchester syndrome: - Genetic Testing Registry: Winchester syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Wolman disease ? | Wolman disease is a rare inherited condition involving the breakdown and use of fats and cholesterol in the body (lipid metabolism). In affected individuals, harmful amounts of lipids accumulate in the spleen, liver, bone marrow, small intestine, small hormone-producing glands on top of each kidney (adrenal glands), and lymph nodes. In addition to fat deposits, calcium deposits in the adrenal glands are also seen. Infants with Wolman disease are healthy and active at birth but soon develop signs and symptoms of the disorder. These may include an enlarged liver and spleen (hepatosplenomegaly), poor weight gain, low muscle tone, a yellow tint to the skin and the whites of the eyes (jaundice), vomiting, diarrhea, developmental delay, low amounts of iron in the blood (anemia), and poor absorption of nutrients from food. Children affected by this condition develop severe malnutrition and generally do not survive past early childhood. |
frequency | How many people are affected by Wolman disease ? | Wolman disease is estimated to occur in 1 in 350,000 newborns. |
genetic changes | What are the genetic changes related to Wolman disease ? | Mutations in the LIPA gene cause Wolman disease. The LIPA gene provides instructions for producing an enzyme called lysosomal acid lipase. This enzyme is found in the lysosomes (compartments that digest and recycle materials in the cell), where it processes lipids such as cholesteryl esters and triglycerides so they can be used by the body. Mutations in this gene lead to a shortage of lysosomal acid lipase and the accumulation of triglycerides, cholesteryl esters, and other kinds of fats within the cells and tissues of affected individuals. This accumulation as well as malnutrition caused by the body's inability to use lipids properly result in the signs and symptoms of Wolman disease. |
inheritance | Is Wolman disease inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for Wolman disease ? | These resources address the diagnosis or management of Wolman disease: - Genetic Testing Registry: Lysosomal acid lipase deficiency These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) purine nucleoside phosphorylase deficiency ? | Purine nucleoside phosphorylase deficiency is one of several disorders that damage the immune system and cause severe combined immunodeficiency (SCID). People with SCID lack virtually all immune protection from foreign invaders such as bacteria, viruses, and fungi. Affected individuals are prone to repeated and persistent infections that can be very serious or life-threatening. These infections are often caused by "opportunistic" organisms that ordinarily do not cause illness in people with a normal immune system. Infants with SCID typically grow much more slowly than healthy children and experience pneumonia, chronic diarrhea, and widespread skin rashes. Without successful treatment to restore immune function, children with SCID usually do not survive past early childhood. About two-thirds of individuals with purine nucleoside phosphorylase deficiency have neurological problems, which may include developmental delay, intellectual disability, difficulties with balance and coordination (ataxia), and muscle stiffness (spasticity). People with purine nucleoside phosphorylase deficiency are also at increased risk of developing autoimmune disorders, which occur when the immune system malfunctions and attacks the body's tissues and organs. |
frequency | How many people are affected by purine nucleoside phosphorylase deficiency ? | Purine nucleoside phosphorylase deficiency is rare; only about 70 affected individuals have been identified. This disorder accounts for approximately 4 percent of all SCID cases. |
genetic changes | What are the genetic changes related to purine nucleoside phosphorylase deficiency ? | Purine nucleoside phosphorylase deficiency is caused by mutations in the PNP gene. The PNP gene provides instructions for making an enzyme called purine nucleoside phosphorylase. This enzyme is found throughout the body but is most active in specialized white blood cells called lymphocytes. These cells protect the body against potentially harmful invaders by making immune proteins called antibodies that tag foreign particles and germs for destruction or by directly attacking virus-infected cells. Lymphocytes are produced in specialized lymphoid tissues including the thymus and lymph nodes and then released into the blood. The thymus is a gland located behind the breastbone; lymph nodes are found throughout the body. Lymphocytes in the blood and in lymphoid tissues make up the immune system. Purine nucleoside phosphorylase is known as a housekeeping enzyme because it clears away waste molecules that are generated when DNA is broken down. Mutations in the PNP gene reduce or eliminate the activity of purine nucleoside phosphorylase. The resulting excess of waste molecules and further reactions involving them lead to the buildup of a substance called deoxyguanosine triphosphate (dGTP) to levels that are toxic to lymphocytes. Immature lymphocytes in the thymus are particularly vulnerable to a toxic buildup of dGTP, which damages them and triggers their self-destruction (apoptosis). The number of lymphocytes in other lymphoid tissues is also greatly reduced, resulting in the immune deficiency characteristic of purine nucleoside phosphorylase deficiency. |
inheritance | Is purine nucleoside phosphorylase deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for purine nucleoside phosphorylase deficiency ? | These resources address the diagnosis or management of purine nucleoside phosphorylase deficiency: - Baby's First Test: Severe Combined Immunodeficiency - Genetic Testing Registry: Purine-nucleoside phosphorylase deficiency - National Marrow Donor Program These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Cushing disease ? | Cushing disease is caused by elevated levels of a hormone called cortisol, which leads to a wide variety of signs and symptoms. This condition usually occurs in adults between the ages of 20 and 50; however, children may also be affected. The first sign of this condition is usually weight gain around the trunk and in the face. Affected individuals may get stretch marks (striae) on their thighs and abdomen and bruise easily. Individuals with Cushing disease can develop a hump on their upper back caused by abnormal deposits of fat. People with this condition can have muscle weakness, severe tiredness, and progressively thin and brittle bones that are prone to fracture (osteoporosis). They also have a weakened immune system and are at an increased risk of infections. Cushing disease can cause mood disorders such as anxiety, irritability, and depression. This condition can also affect a person's concentration and memory. People with Cushing disease have an increased chance of developing high blood pressure (hypertension) and diabetes. Women with Cushing disease may experience irregular menstruation and have excessive hair growth (hirsutism) on their face, abdomen, and legs. Men with Cushing disease may have erectile dysfunction. Children with Cushing disease typically experience slow growth. |
frequency | How many people are affected by Cushing disease ? | Cushing disease is estimated to occur in 10 to 15 per million people worldwide. For reasons that are unclear, Cushing disease affects females more often than males. |
genetic changes | What are the genetic changes related to Cushing disease ? | The genetic cause of Cushing disease is often unknown. In only a few instances, mutations in certain genes have been found to lead to Cushing disease. These genetic changes are called somatic mutations. They are acquired during a person's lifetime and are present only in certain cells. The genes involved often play a role in regulating the activity of hormones. Cushing disease is caused by an increase in the hormone cortisol, which helps maintain blood sugar levels, protects the body from stress, and stops (suppresses) inflammation. Cortisol is produced by the adrenal glands, which are small glands located at the top of each kidney. The production of cortisol is triggered by the release of a hormone called adrenocorticotropic hormone (ACTH) from the pituitary gland, located at the base of the brain. The adrenal and pituitary glands are part of the hormone-producing (endocrine) system in the body that regulates development, metabolism, mood, and many other processes. Cushing disease occurs when a noncancerous (benign) tumor called an adenoma forms in the pituitary gland, causing excessive release of ACTH and, subsequently, elevated production of cortisol. Prolonged exposure to increased cortisol levels results in the signs and symptoms of Cushing disease: changes to the amount and distribution of body fat, decreased muscle mass leading to weakness and reduced stamina, thinning skin causing stretch marks and easy bruising, thinning of the bones resulting in osteoporosis, increased blood pressure, impaired regulation of blood sugar leading to diabetes, a weakened immune system, neurological problems, irregular menstruation in women, and slow growth in children. The overactive adrenal glands that produce cortisol may also produce increased amounts of male sex hormones (androgens), leading to hirsutism in females. The effect of the excess androgens on males is unclear. Most often, Cushing disease occurs alone, but rarely, it appears as a symptom of genetic syndromes that have pituitary adenomas as a feature, such as multiple endocrine neoplasia type 1 (MEN1) or familial isolated pituitary adenoma (FIPA). Cushing disease is a subset of a larger condition called Cushing syndrome, which results when cortisol levels are increased by one of a number of possible causes. Sometimes adenomas that occur in organs or tissues other than the pituitary gland, such as adrenal gland adenomas, can also increase cortisol production, causing Cushing syndrome. Certain prescription drugs can result in an increase in cortisol production and lead to Cushing syndrome. Sometimes prolonged periods of stress or depression can cause an increase in cortisol levels; when this occurs, the condition is known as pseudo-Cushing syndrome. Not accounting for increases in cortisol due to prescription drugs, pituitary adenomas cause the vast majority of Cushing syndrome in adults and children. |
inheritance | Is Cushing disease inherited ? | Most cases of Cushing disease are sporadic, which means they occur in people with no history of the disorder in their family. Rarely, the condition has been reported to run in families; however, it does not have a clear pattern of inheritance. The various syndromes that have Cushing disease as a feature can have different inheritance patterns. Most of these disorders are inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. |
treatment | What are the treatments for Cushing disease ? | These resources address the diagnosis or management of Cushing disease: - Genetic Testing Registry: Pituitary dependent hypercortisolism - MedlinePlus Encyclopedia: Cortisol Level - MedlinePlus Encyclopedia: Cushing Disease - The Endocrine Society's Clinical Guidelines: The Diagnosis of Cushing's Syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) pseudoxanthoma elasticum ? | Pseudoxanthoma elasticum (PXE) is a progressive disorder that is characterized by the accumulation of deposits of calcium and other minerals (mineralization) in elastic fibers. Elastic fibers are a component of connective tissue, which provides strength and flexibility to structures throughout the body. In PXE, mineralization can affect elastic fibers in the skin, eyes, and blood vessels, and less frequently in other areas such as the digestive tract. People with PXE may have yellowish bumps called papules on their necks, underarms, and other areas of skin that touch when a joint bends (flexor areas). They may also have abnormalities in the eyes, such as a change in the pigmented cells of the retina (the light-sensitive layer of cells at the back of the eye) known as peau d'orange. Another eye abnormality known as angioid streaks occurs when tiny breaks form in the layer of tissue under the retina called Bruch's membrane. Bleeding and scarring of the retina may also occur, which can cause vision loss. Mineralization of the blood vessels that carry blood from the heart to the rest of the body (arteries) may cause other signs and symptoms of PXE. For example, people with this condition can develop narrowing of the arteries (arteriosclerosis) or a condition called claudication that is characterized by cramping and pain during exercise due to decreased blood flow to the arms and legs. Rarely, bleeding from blood vessels in the digestive tract may also occur. |
frequency | How many people are affected by pseudoxanthoma elasticum ? | PXE affects approximately 1 in 50,000 people worldwide. For reasons that are unclear, this disorder is diagnosed twice as frequently in females as in males. |
genetic changes | What are the genetic changes related to pseudoxanthoma elasticum ? | Mutations in the ABCC6 gene cause PXE. This gene provides instructions for making a protein called MRP6 (also known as the ABCC6 protein). This protein is found primarily in cells of the liver and kidneys, with small amounts in other tissues, including the skin, stomach, blood vessels, and eyes. MRP6 is thought to transport certain substances across the cell membrane; however, the substances have not been identified. Some studies suggest that the MRP6 protein stimulates the release of a molecule called adenosine triphosphate (ATP) from cells through an unknown mechanism. ATP can be broken down into other molecules, including adenosine monophosphate (AMP) and pyrophosphate. Pyrophosphate helps control deposition of calcium and other minerals in the body. Other studies suggest that a substance transported by MRP6 is involved in the breakdown of ATP. This unidentified substance is thought to help prevent mineralization of tissues. Mutations in the ABCC6 gene lead to an absent or nonfunctional MRP6 protein. It is unclear how a lack of properly functioning MRP6 protein leads to PXE. This shortage may impair the release of ATP from cells. As a result, little pyrophosphate is produced, and calcium and other minerals accumulate in elastic fibers of the skin, eyes, blood vessels and other tissues affected by PXE. Alternatively, a lack of functioning MRP6 may impair the transport of a substance that would normally prevent mineralization, leading to the abnormal accumulation of calcium and other minerals characteristic of PXE. |
inheritance | Is pseudoxanthoma elasticum inherited ? | PXE is inherited in an autosomal recessive manner, 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. In a few cases, an affected individual has one affected parent and one parent without the signs and symptoms of the disorder. This situation resembles autosomal dominant inheritance, in which one copy of an altered gene in each cell is sufficient to cause a disorder and the mutation is typically inherited from one affected parent. In these cases of PXE, however, the parent without apparent symptoms has an ABCC6 gene mutation. The affected offspring inherits two altered genes, one from each parent. This appearance of autosomal dominant inheritance when the pattern is actually autosomal recessive is called pseudodominance. |
treatment | What are the treatments for pseudoxanthoma elasticum ? | These resources address the diagnosis or management of pseudoxanthoma elasticum: - Gene Review: Gene Review: Pseudoxanthoma Elasticum - Genetic Testing Registry: Pseudoxanthoma elasticum These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) beta-mannosidosis ? | Beta-mannosidosis is a rare inherited disorder affecting the way certain sugar molecules are processed in the body. Signs and symptoms of beta-mannosidosis vary widely in severity, and the age of onset ranges between infancy and adolescence. Almost all individuals with beta-mannosidosis experience intellectual disability, and some have delayed motor development and seizures. Affected individuals may be extremely introverted, prone to depression, or have behavioral problems such as hyperactivity, impulsivity or aggression. People with beta-mannosidosis may experience an increased risk of respiratory and ear infections, hearing loss, speech impairment, swallowing difficulties, poor muscle tone (hypotonia), and reduced sensation or other nervous system abnormalities in the extremities (peripheral neuropathy). They may also exhibit distinctive facial features and clusters of enlarged blood vessels forming small, dark red spots on the skin (angiokeratomas). |
frequency | How many people are affected by beta-mannosidosis ? | Beta-mannosidosis is believed to be a very rare disorder. Approximately 20 affected individuals have been reported worldwide. It is difficult to determine the specific incidence of beta-mannosidosis, because people with mild or non-specific symptoms may never be diagnosed. |
genetic changes | What are the genetic changes related to beta-mannosidosis ? | Mutations in the MANBA gene cause beta-mannosidosis. The MANBA gene provides instructions for making the enzyme beta-mannosidase. This enzyme works in the lysosomes, which are compartments that digest and recycle materials in the cell. Within lysosomes, the enzyme helps break down complexes of sugar molecules (oligosaccharides) attached to certain proteins (glycoproteins). Beta-mannosidase is involved in the last step of this process, helping to break down complexes of two sugar molecules (disaccharides) containing a sugar molecule called mannose. Mutations in the MANBA gene interfere with the ability of the beta-mannosidase enzyme to perform its role in breaking down mannose-containing disaccharides. These disaccharides gradually accumulate in the lysosomes and cause cells to malfunction, resulting in the signs and symptoms of beta-mannosidosis. |
inheritance | Is beta-mannosidosis inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for beta-mannosidosis ? | These resources address the diagnosis or management of beta-mannosidosis: - Genetic Testing Registry: Beta-D-mannosidosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) spondylocostal dysostosis ? | Spondylocostal dysostosis is a group of conditions characterized by abnormal development of bones in the spine and ribs. The bones of the spine (vertebrae) are misshapen and abnormally joined together (fused). Many people with this condition have abnormal side-to-side curvature of the spine (scoliosis) due to malformation of the vertebrae. In addition to spine abnormalities, some of the rib bones may be fused together or missing. Affected individuals have short, rigid necks and short midsections because of the bone malformations. As a result, people with spondylocostal dysostosis have short bodies but normal length arms and legs, called short-trunk dwarfism. The spine and rib abnormalities cause other signs and symptoms of spondylocostal dysostosis. Infants with this condition are born with small chests that cannot expand adequately, often leading to life-threatening breathing problems. As the lungs expand in the narrow chest, the muscle that separates the abdomen from the chest cavity (the diaphragm) is forced down and the abdomen is pushed out. The increased pressure in the abdomen can cause a soft out-pouching around the lower abdomen (inguinal hernia), particularly in males with spondylocostal dysostosis. There are several types of spondylocostal dysostosis, designated types 1 through 4 and the autosomal dominant (AD) type. These types have similar features and are distinguished by their genetic cause and inheritance pattern. Spondylocostal dysostosis has often been grouped with a similar condition called spondylothoracic dysostosis, and both are called Jarcho-Levin syndrome; however, they are now considered distinct conditions. |
frequency | How many people are affected by spondylocostal dysostosis ? | Spondylocostal dysostosis is a rare condition, although its exact prevalence is unknown. |
genetic changes | What are the genetic changes related to spondylocostal dysostosis ? | Mutations in at least four genes are known to cause spondylocostal dysostosis: Mutations in the DLL3 gene cause spondylocostal dysostosis type 1; mutations in the MESP2 gene cause spondylocostal dysostosis type 2; mutations in the LFNG gene cause spondylocostal dysostosis type 3; and mutations in the HES7 gene cause spondylocostal dysostosis type 4. The genetic cause of AD spondylocostal dysostosis is unknown. The DLL3, MESP2, LFNG, and HES7 genes play a role in the Notch signaling pathway, an important pathway in embryonic development. One of the functions of the Notch pathway is separating future vertebrae from one another during early development, a process called somite segmentation. When this pathway is disrupted, somite segmentation does not occur properly, resulting in the malformation and fusion of the bones of the spine and ribs seen in spondylocostal dysostosis. Mutations in the four identified genes account for approximately 25 percent of diagnosed spondylocostal dysostosis. Researchers suggest that additional genes in the Notch signaling pathway might also be involved. |
inheritance | Is spondylocostal dysostosis inherited ? | Spondylocostal dysostosis can have different inheritance patterns. Types 1, 2, 3, and 4 are 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. AD spondylocostal dysostosis is inherited in an autosomal dominant pattern. Autosomal dominant inheritance means that one copy of an altered gene in each cell is sufficient to cause the disorder, although in these cases no causative genes have been identified. The signs and symptoms of spondylocostal dysostosis are typically more severe with autosomal recessive inheritance. |
treatment | What are the treatments for spondylocostal dysostosis ? | These resources address the diagnosis or management of spondylocostal dysostosis: - Gene Review: Gene Review: Spondylocostal Dysostosis, Autosomal Recessive - Genetic Testing Registry: Jarcho-Levin syndrome - Genetic Testing Registry: Spondylocostal dysostosis 1 - Genetic Testing Registry: Spondylocostal dysostosis 2 - Genetic Testing Registry: Spondylocostal dysostosis 3 - Genetic Testing Registry: Spondylocostal dysostosis 4, autosomal recessive - KidsHealth: X-Ray Exam (Scoliosis) - MedlinePlus Encyclopedia: Scoliosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) biotinidase deficiency ? | Biotinidase deficiency is an inherited disorder in which the body is unable to recycle the vitamin biotin. If this condition is not recognized and treated, its signs and symptoms typically appear within the first few months of life, although it can also become apparent later in childhood. Profound biotinidase deficiency, the more severe form of the condition, can cause seizures, weak muscle tone (hypotonia), breathing problems, hearing and vision loss, problems with movement and balance (ataxia), skin rashes, hair loss (alopecia), and a fungal infection called candidiasis. Affected children also have delayed development. Lifelong treatment can prevent these complications from occurring or improve them if they have already developed. Partial biotinidase deficiency is a milder form of this condition. Without treatment, affected children may experience hypotonia, skin rashes, and hair loss, but these problems may appear only during illness, infection, or other times of stress. |
frequency | How many people are affected by biotinidase deficiency ? | Profound or partial biotinidase deficiency occurs in approximately 1 in 60,000 newborns |
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