problem
stringlengths 16
191
| explanation
stringlengths 6
29k
⌀ | type
stringlengths 3
136
⌀ |
|---|---|---|
What is (are) sialidosis ? | Sialidosis is a severe inherited disorder that affects many organs and tissues, including the nervous system. This disorder is divided into two types, which are distinguished by the age at which symptoms appear and the severity of features. Sialidosis type I, also referred to as cherry-red spot myoclonus syndrome, is the less severe form of this condition. People with type I develop signs and symptoms of sialidosis in their teens or twenties. Initially, affected individuals experience problems walking (gait disturbance) and/or a loss of sharp vision (reduced visual acuity). Individuals with sialidosis type I also experience muscle twitches (myoclonus), difficulty coordinating movements (ataxia), leg tremors, and seizures. The myoclonus worsens over time, causing difficulty sitting, standing, or walking. People with sialidosis type I eventually require wheelchair assistance. Affected individuals have progressive vision problems, including impaired color vision or night blindness. An eye abnormality called a cherry-red spot, which can be identified with an eye examination, is characteristic of this disorder. Sialidosis type I does not affect intelligence or life expectancy. Sialidosis type II, the more severe type of the disorder, is further divided into congenital, infantile, and juvenile forms. The features of congenital sialidosis type II can develop before birth. This form of sialidosis is associated with an abnormal buildup of fluid in the abdominal cavity (ascites) or widespread swelling before birth caused by fluid accumulation (hydrops fetalis). Affected infants may also have an enlarged liver and spleen (hepatosplenomegaly), abnormal bone development (dysostosis multiplex), and distinctive facial features that are often described as "coarse." As a result of these serious health problems, individuals with congenital sialidosis type II usually are stillborn or die soon after birth. Infantile sialidosis type II shares some features with the congenital form, although the signs and symptoms are slightly less severe and begin within the first year of life. Features of the infantile form include hepatosplenomegaly, dysostosis multiplex, "coarse" facial features, short stature, and intellectual disability. As children with infantile sialidosis type II get older, they may develop myoclonus and cherry-red spots. Other signs and symptoms include hearing loss, overgrowth of the gums (gingival hyperplasia), and widely spaced teeth. Affected individuals may survive into childhood or adolescence. The juvenile form has the least severe signs and symptoms of the different forms of sialidosis type II. Features of this condition usually appear in late childhood and may include mildly "coarse" facial features, mild bone abnormalities, cherry-red spots, myoclonus, intellectual disability, and dark red spots on the skin (angiokeratomas). The life expectancy of individuals with juvenile sialidosis type II varies depending on the severity of symptoms. | sialidosis |
How many people are affected by sialidosis ? | The overall prevalence of sialidosis is unknown. Sialidosis type I appears to be more common in people with Italian ancestry. | sialidosis |
What are the genetic changes related to sialidosis ? | Mutations in the NEU1 gene cause sialidosis. This gene provides instructions for making an enzyme called neuraminidase 1 (NEU1), which is found in lysosomes. Lysosomes are compartments within the cell that use enzymes to digest and recycle materials. The NEU1 enzyme helps break down large sugar molecules attached to certain proteins by removing a substance known as sialic acid. Mutations in the NEU1 gene lead to a shortage (deficiency) of the NEU1 enzyme. When this enzyme is lacking, sialic acid-containing compounds accumulate inside lysosomes. Conditions such as sialidosis that cause molecules to build up inside lysosomes are called lysosomal storage disorders. People with sialidosis type II have mutations that severely reduce or eliminate NEU1 enzyme activity. Individuals with sialidosis type I have mutations that result in some functional NEU1 enzyme. It is unclear exactly how the accumulation of large molecules within lysosomes leads to the signs and symptoms of sialidosis. | sialidosis |
Is sialidosis 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. | sialidosis |
What are the treatments for sialidosis ? | These resources address the diagnosis or management of sialidosis: - Genetic Testing Registry: Sialidosis type I - Genetic Testing Registry: Sialidosis, type II - MedlinePlus Encyclopedia: Ascites - MedlinePlus Encyclopedia: Hydrops Fetalis 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 | sialidosis |
What is (are) Coffin-Siris syndrome ? | Coffin-Siris syndrome is a condition that affects several body systems. Although there are many variable signs and symptoms, hallmarks of this condition include developmental disability, abnormalities of the fifth (pinky) fingers or toes, and characteristic facial features. Most affected individuals have mild to severe intellectual disability or delayed development of speech and motor skills such as sitting and walking. Another feature of Coffin-Siris syndrome is underdevelopment (hypoplasia) of the tips of the fingers or toes, or hypoplasia or absence of the nails. These abnormalities are most common on the fifth fingers or toes. In addition, most affected individuals have facial features described as coarse. These typically include a wide nose with a flat nasal bridge, a wide mouth with thick lips, and thick eyebrows and eyelashes. Affected individuals can have excess hair on other parts of the face and body (hirsutism), but scalp hair is often sparse. There is a range of facial features seen in people with Coffin-Siris syndrome, and not all affected individuals have the typical features. In addition, people with this condition may have an abnormally small head (microcephaly). Additionally, some infants and children with Coffin-Siris syndrome have frequent respiratory infections, difficulty feeding, and an inability to gain weight at the expected rate (failure to thrive). Other signs and symptoms that may occur in people with this condition include short stature, low muscle tone (hypotonia), and abnormally loose (lax) joints. Abnormalities of the eyes, brain, heart, and kidneys may also be present. | Coffin-Siris syndrome |
How many people are affected by Coffin-Siris syndrome ? | Coffin-Siris syndrome is a rare condition that is diagnosed in females more frequently than in males. Approximately 140 cases have been reported in the medical literature. | Coffin-Siris syndrome |
What are the genetic changes related to Coffin-Siris syndrome ? | Coffin-Siris syndrome is caused by mutations in the ARID1A, ARID1B, SMARCA4, SMARCB1, or SMARCE1 gene. Each of these genes provides instructions for making one piece (subunit) of several different SWI/SNF protein complexes. SWI/SNF complexes regulate gene activity (expression) by a process known as chromatin remodeling. Chromatin is the network of DNA and protein that packages DNA into chromosomes. The structure of chromatin can be changed (remodeled) to alter how tightly regions of DNA are packaged. Chromatin remodeling is one way gene expression is regulated during development; when DNA is tightly packed, gene expression is often lower than when DNA is loosely packed. Through their ability to regulate gene activity, SWI/SNF complexes are involved in many processes, including repairing damaged DNA; copying (replicating) DNA; and controlling the growth, division, and maturation (differentiation) of cells. Although it is unclear what effect mutations in these genes have on SWI/SNF complexes, researchers suggest that the mutations result in abnormal chromatin remodeling. Disturbance of this process alters the activity of many genes and disrupts several cellular processes, which could explain the diverse signs and symptoms of Coffin-Siris syndrome. | Coffin-Siris syndrome |
Is Coffin-Siris syndrome inherited ? | Coffin-Siris syndrome appears to follow an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the disorder. However, the condition is not usually inherited from an affected parent, but occurs from new (de novo) mutations in the gene that likely occur during early embryonic development. | Coffin-Siris syndrome |
What are the treatments for Coffin-Siris syndrome ? | These resources address the diagnosis or management of Coffin-Siris syndrome: - Gene Review: Gene Review: Coffin-Siris Syndrome - Genetic Testing Registry: Coffin-Siris 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 | Coffin-Siris syndrome |
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. | Pompe disease |
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. | Pompe disease |
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. | Pompe disease |
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. | Pompe disease |
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 | Pompe disease |
What is (are) dentatorubral-pallidoluysian atrophy ? | Dentatorubral-pallidoluysian atrophy, commonly known as DRPLA, is a progressive brain disorder that causes involuntary movements, mental and emotional problems, and a decline in thinking ability. The average age of onset of DRPLA is 30 years, but this condition can appear anytime from infancy to mid-adulthood. The signs and symptoms of DRPLA differ somewhat between affected children and adults. When DRPLA appears before age 20, it most often involves episodes of involuntary muscle jerking or twitching (myoclonus), seizures, behavioral changes, intellectual disability, and problems with balance and coordination (ataxia). When DRPLA begins after age 20, the most frequent signs and symptoms are ataxia, uncontrollable movements of the limbs (choreoathetosis), psychiatric symptoms such as delusions, and deterioration of intellectual function (dementia). | dentatorubral-pallidoluysian atrophy |
How many people are affected by dentatorubral-pallidoluysian atrophy ? | DRPLA is most common in the Japanese population, where it has an estimated incidence of 2 to 7 per million people. This condition has also been seen in families from North America and Europe. Although DRPLA is rare in the United States, it has been studied in a large African American family from the Haw River area of North Carolina. When the family was first identified, researchers named the disorder Haw River syndrome. Later, researchers determined that Haw River syndrome and DRPLA are the same condition. | dentatorubral-pallidoluysian atrophy |
What are the genetic changes related to dentatorubral-pallidoluysian atrophy ? | DRPLA is caused by a mutation in the ATN1 gene. This gene provides instructions for making a protein called atrophin 1. Although the function of atrophin 1 is unclear, it likely plays an important role in nerve cells (neurons) in many areas of the brain. The ATN1 mutation that underlies DRPLA involves a DNA segment known as a CAG trinucleotide repeat. This segment is made up of a series of three DNA building blocks (cytosine, adenine, and guanine) that appear multiple times in a row. Normally, this segment is repeated 6 to 35 times within the ATN1 gene. In people with DRPLA, the CAG segment is repeated at least 48 times, and the repeat region may be two or three times its usual length. The abnormally long CAG trinucleotide repeat changes the structure of atrophin 1. This altered protein accumulates in neurons and interferes with normal cell functions. The dysfunction and eventual death of these neurons lead to uncontrolled movements, intellectual decline, and the other characteristic features of DRPLA. | dentatorubral-pallidoluysian atrophy |
Is dentatorubral-pallidoluysian atrophy inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition. As the altered ATN1 gene is passed from one generation to the next, the size of the CAG trinucleotide repeat often increases in size. Larger repeat expansions are usually associated with an earlier onset of the disorder and more severe signs and symptoms. This phenomenon is called anticipation. Anticipation tends to be more prominent when the ATN1 gene is inherited from a person's father (paternal inheritance) than when it is inherited from a person's mother (maternal inheritance). | dentatorubral-pallidoluysian atrophy |
What are the treatments for dentatorubral-pallidoluysian atrophy ? | These resources address the diagnosis or management of DRPLA: - Gene Review: Gene Review: DRPLA - Genetic Testing Registry: Dentatorubral pallidoluysian atrophy - MedlinePlus Encyclopedia: Dementia - MedlinePlus Encyclopedia: Epilepsy 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 | dentatorubral-pallidoluysian atrophy |
What is (are) X-linked sideroblastic anemia and ataxia ? | X-linked sideroblastic anemia and ataxia is a rare condition characterized by a blood disorder called sideroblastic anemia and movement problems known as ataxia. This condition occurs only in males. Sideroblastic anemia results when developing red blood cells called erythroblasts do not make enough hemoglobin, which is the protein that carries oxygen in the blood. People with X-linked sideroblastic anemia and ataxia have mature red blood cells that are smaller than normal (microcytic) and appear pale (hypochromic) because of the shortage of hemoglobin. This disorder also leads to an abnormal accumulation of iron in red blood cells. The iron-loaded erythroblasts, which are present in bone marrow, are called ring sideroblasts. These abnormal cells give the condition its name. Unlike other forms of sideroblastic anemia, X-linked sideroblastic anemia and ataxia does not cause a potentially dangerous buildup of iron in the body. The anemia is typically mild and usually does not cause any symptoms. X-linked sideroblastic anemia and ataxia causes problems with balance and coordination that appear early in life. The ataxia primarily affects the trunk, making it difficult to sit, stand, and walk unassisted. In addition to ataxia, people with this condition often have trouble coordinating movements that involve judging distance or scale (dysmetria) and find it difficult to make rapid, alternating movements (dysdiadochokinesis). Mild speech difficulties (dysarthria), tremor, and abnormal eye movements have also been reported in some affected individuals. | X-linked sideroblastic anemia and ataxia |
How many people are affected by X-linked sideroblastic anemia and ataxia ? | X-linked sideroblastic anemia and ataxia is a rare disorder; only a few affected families have been reported. | X-linked sideroblastic anemia and ataxia |
What are the genetic changes related to X-linked sideroblastic anemia and ataxia ? | Mutations in the ABCB7 gene cause X-linked sideroblastic anemia and ataxia. The ABCB7 gene provides instructions for making a protein that is critical for heme production. Heme is a component of the hemoglobin protein, which is vital for supplying oxygen to the entire body. The ABCB7 protein also plays a role in the formation of certain proteins containing clusters of iron and sulfur atoms. Overall, researchers believe that the ABCB7 protein helps maintain an appropriate balance of iron (iron homeostasis) in developing red blood cells. ABCB7 mutations slightly alter the structure of the ABCB7 protein, disrupting its usual role in heme production and iron homeostasis. Anemia results when heme cannot be produced normally, and therefore not enough hemoglobin is made. It is unclear how changes in the ABCB7 gene lead to ataxia and other problems with movement. | X-linked sideroblastic anemia and ataxia |
Is X-linked sideroblastic anemia and ataxia 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. In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. Carriers of an ABCB7 mutation can pass on the mutated gene but do not develop ataxia or other health problems associated with X-linked sideroblastic anemia and ataxia. However, carriers may have abnormally small, pale red blood cells and related changes that can be detected with a blood test. | X-linked sideroblastic anemia and ataxia |
What are the treatments for X-linked sideroblastic anemia and ataxia ? | These resources address the diagnosis or management of X-linked sideroblastic anemia and ataxia: - Gene Review: Gene Review: X-Linked Sideroblastic Anemia and Ataxia - Genetic Testing Registry: Anemia sideroblastic and spinocerebellar ataxia - MedlinePlus Encyclopedia: Anemia 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 | X-linked sideroblastic anemia and ataxia |
What is (are) hypercholesterolemia ? | Hypercholesterolemia is a condition characterized by very high levels of cholesterol in the blood. Cholesterol is a waxy, fat-like substance that is produced in the body and obtained from foods that come from animals (particularly egg yolks, meat, poultry, fish, and dairy products). The body needs this substance to build cell membranes, make certain hormones, and produce compounds that aid in fat digestion. Too much cholesterol, however, increases a person's risk of developing heart disease. People with hypercholesterolemia have a high risk of developing a form of heart disease called coronary artery disease. This condition occurs when excess cholesterol in the bloodstream is deposited in the walls of blood vessels, particularly in the arteries that supply blood to the heart (coronary arteries). The abnormal buildup of cholesterol forms clumps (plaque) that narrow and harden artery walls. As the clumps get bigger, they can clog the arteries and restrict the flow of blood to the heart. The buildup of plaque in coronary arteries causes a form of chest pain called angina and greatly increases a person's risk of having a heart attack. Inherited forms of hypercholesterolemia can also cause health problems related to the buildup of excess cholesterol in other tissues. If cholesterol accumulates in tendons, it causes characteristic growths called tendon xanthomas. These growths most often affect the Achilles tendons and tendons in the hands and fingers. Yellowish cholesterol deposits under the skin of the eyelids are known as xanthelasmata. Cholesterol can also accumulate at the edges of the clear, front surface of the eye (the cornea), leading to a gray-colored ring called an arcus cornealis. | hypercholesterolemia |
How many people are affected by hypercholesterolemia ? | More than 34 million American adults have elevated blood cholesterol levels (higher than 240 mg/dL). Inherited forms of hypercholesterolemia, which cause even higher levels of cholesterol, occur less frequently. The most common inherited form of high cholesterol is called familial hypercholesterolemia. This condition affects about 1 in 500 people in most countries. Familial hypercholesterolemia occurs more frequently in certain populations, including Afrikaners in South Africa, French Canadians, Lebanese, and Finns. | hypercholesterolemia |
What are the genetic changes related to hypercholesterolemia ? | Mutations in the APOB, LDLR, LDLRAP1, and PCSK9 genes cause hypercholesterolemia. High blood cholesterol levels typically result from a combination of genetic and environmental risk factors. Lifestyle choices including diet, exercise, and tobacco smoking strongly influence the amount of cholesterol in the blood. Additional factors that impact cholesterol levels include a person's gender, age, and health problems such as diabetes and obesity. A small percentage of all people with high cholesterol have an inherited form of hypercholesterolemia. The most common cause of inherited high cholesterol is a condition known as familial hypercholesterolemia, which results from mutations in the LDLR gene. The LDLR gene provides instructions for making a protein called a low-density lipoprotein receptor. This type of receptor binds to particles called low-density lipoproteins (LDLs), which are the primary carriers of cholesterol in the blood. By removing low-density lipoproteins from the bloodstream, these receptors play a critical role in regulating cholesterol levels. Some LDLR mutations reduce the number of low-density lipoprotein receptors produced within cells. Other mutations disrupt the receptors' ability to remove low-density lipoproteins from the bloodstream. As a result, people with mutations in the LDLR gene have very high levels of blood cholesterol. As the excess cholesterol circulates through the bloodstream, it is deposited abnormally in tissues such as the skin, tendons, and arteries that supply blood to the heart. Less commonly, hypercholesterolemia can be caused by mutations in the APOB, LDLRAP1, or PCSK9 gene. Changes in the APOB gene result in a form of inherited hypercholesterolemia known as familial defective apolipoprotein B-100 (FDB). LDLRAP1 mutations are responsible for another type of inherited high cholesterol, autosomal recessive hypercholesterolemia (ARH). Proteins produced from the APOB, LDLRAP1, and PCSK9 genes are essential for the normal function of low-density lipoprotein receptors. Mutations in any of these genes prevent the cell from making functional receptors or alter the receptors' function. Hypercholesterolemia results when low-density lipoprotein receptors are unable to remove cholesterol from the blood effectively. Researchers are working to identify and characterize additional genes that may influence cholesterol levels and the risk of heart disease in people with hypercholesterolemia. | hypercholesterolemia |
Is hypercholesterolemia inherited ? | Most cases of high cholesterol are not caused by a single inherited condition, but result from a combination of lifestyle choices and the effects of variations in many genes. Inherited forms of hypercholesterolemia resulting from mutations in the LDLR, APOB, or PCSK9 gene have an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means one copy of an altered gene in each cell is sufficient to cause the disorder. An affected person typically inherits one altered copy of the gene from an affected parent and one normal copy of the gene from the other parent. Rarely, a person with familial hypercholesterolemia is born with two mutated copies of the LDLR gene. This situation occurs when the person has two affected parents, each of whom passes on one altered copy of the gene. The presence of two LDLR mutations results in a more severe form of hypercholesterolemia that usually appears in childhood. When hypercholesterolemia is caused by mutations in the LDLRAP1 gene, the condition is inherited in an autosomal recessive pattern. Autosomal recessive inheritance means the condition results from two altered copies of the gene in each cell. The parents of an individual with autosomal recessive hypercholesterolemia each carry one copy of the altered gene, but their blood cholesterol levels are usually in the normal range. | hypercholesterolemia |
What are the treatments for hypercholesterolemia ? | These resources address the diagnosis or management of hypercholesterolemia: - Gene Review: Gene Review: Familial Hypercholesterolemia - GeneFacts: Familial Hypercholesterolemia: Diagnosis - GeneFacts: Familial Hypercholesterolemia: Management - Genetic Testing Registry: Familial hypercholesterolemia - Genetic Testing Registry: Hypercholesterolemia, autosomal dominant, 3 - Genetic Testing Registry: Hypercholesterolemia, autosomal dominant, type B - Genetic Testing Registry: Hypercholesterolemia, autosomal recessive - Genomics Education Programme (UK) - MedlinePlus Encyclopedia: Familial hypercholesterolemia - MedlinePlus Encyclopedia: High blood cholesterol and triglycerides - MedlinePlus Encyclopedia: Xanthoma 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 | hypercholesterolemia |
What is (are) glycogen storage disease type III ? | Glycogen storage disease type III (also known as GSDIII or Cori disease) is an inherited disorder caused by the buildup of a complex sugar called glycogen in the body's cells. The accumulated glycogen is structurally abnormal and impairs the function of certain organs and tissues, especially the liver and muscles. GSDIII is divided into types IIIa, IIIb, IIIc, and IIId, which are distinguished by their pattern of signs and symptoms. GSD types IIIa and IIIc mainly affect the liver and muscles, and GSD types IIIb and IIId typically affect only the liver. It is very difficult to distinguish between the types of GSDIII that affect the same tissues. GSD types IIIa and IIIb are the most common forms of this condition. Beginning in infancy, individuals with any type of GSDIII may have low blood sugar (hypoglycemia), excess amounts of fats in the blood (hyperlipidemia), and elevated blood levels of liver enzymes. As they get older, children with this condition typically develop an enlarged liver (hepatomegaly). Liver size usually returns to normal during adolescence, but some affected individuals develop chronic liver disease (cirrhosis) and liver failure later in life. People with GSDIII often have slow growth because of their liver problems, which can lead to short stature. In a small percentage of people with GSDIII, noncancerous (benign) tumors called adenomas may form in the liver. Individuals with GSDIIIa may develop muscle weakness (myopathy) later in life. These muscle problems can affect both heart (cardiac) muscle and the muscles that are used for movement (skeletal muscles). Muscle involvement varies greatly among affected individuals. The first signs and symptoms are typically poor muscle tone (hypotonia) and mild myopathy in early childhood. The myopathy may become severe by early to mid-adulthood. Some people with GSDIIIa have a weakened heart muscle (cardiomyopathy), but affected individuals usually do not experience heart failure. Other people affected with GSDIIIa have no cardiac muscle problems. | glycogen storage disease type III |
How many people are affected by glycogen storage disease type III ? | The incidence of GSDIII in the United States is 1 in 100,000 individuals. This condition is seen more frequently in people of North African Jewish ancestry; in this population, 1 in 5,400 individuals are estimated to be affected. GSDIIIa is the most common form of GSDIII, accounting for about 85 percent of all cases. GSDIIIb accounts for about 15 percent of cases. GSD types IIIc and IIId are very rare, and their signs and symptoms are poorly defined. Only a small number of affected individuals have been suspected to have GSD types IIIc and IIId. | glycogen storage disease type III |
What are the genetic changes related to glycogen storage disease type III ? | Mutations in the AGL gene cause GSDIII. The AGL gene provides instructions for making the glycogen debranching enzyme. This enzyme is involved in the breakdown of glycogen, which is a major source of stored energy in the body. Between meals the body breaks down stores of energy, such as glycogen, to use for fuel. Most AGL gene mutations lead to the production of a nonfunctional glycogen debranching enzyme. These mutations typically cause GSD types IIIa and IIIb. The mutations that cause GSD types IIIc and IIId are thought to lead to the production of an enzyme with reduced function. All AGL gene mutations lead to storage of abnormal, partially broken down glycogen molecules within cells. A buildup of abnormal glycogen damages organs and tissues throughout the body, particularly the liver and muscles, leading to the signs and symptoms of GSDIII. | glycogen storage disease type III |
Is glycogen storage disease type III 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. | glycogen storage disease type III |
What are the treatments for glycogen storage disease type III ? | These resources address the diagnosis or management of glycogen storage disease type III: - Gene Review: Gene Review: Glycogen Storage Disease Type III - Genetic Testing Registry: Glycogen storage disease type III 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 | glycogen storage disease type III |
What is (are) tetrasomy 18p ? | Tetrasomy 18p is a chromosomal condition that affects many parts of the body. This condition usually causes feeding difficulties in infancy, delayed development, intellectual disability that is often mild to moderate but can be severe, changes in muscle tone, distinctive facial features, and other birth defects. However, the signs and symptoms vary among affected individuals. Babies with tetrasomy 18p often have trouble feeding and may vomit frequently, which makes it difficult for them to gain weight. Some affected infants also have breathing problems and jaundice, which is a yellowing of the skin and the whites of the eyes. Changes in muscle tone are commonly seen with tetrasomy 18p. Some affected children have weak muscle tone (hypotonia), while others have increased muscle tone (hypertonia) and stiffness (spasticity). These changes contribute to delayed development of motor skills, including sitting, crawling, and walking. Tetrasomy 18p is associated with a distinctive facial appearance that can include unusually shaped and low-set ears, a small mouth, a flat area between the upper lip and the nose (philtrum), and a thin upper lip. Many affected individuals also have a high, arched roof of the mouth (palate), and a few have had a split in the roof of the mouth (cleft palate). Additional features of tetrasomy 18p can include seizures, vision problems, recurrent ear infections, mild to moderate hearing loss, constipation and other gastrointestinal problems, abnormal curvature of the spine (scoliosis or kyphosis), a shortage of growth hormone, and birth defects affecting the heart and other organs. Males with tetrasomy 18p may be born with undescended testes (cryptorchidism) or the opening of the urethra on the underside of the penis (hypospadias). Psychiatric conditions, such as attention deficit hyperactivity disorder (ADHD) and anxiety, as well as social and behavioral challenges have also been reported in some people with tetrasomy 18p. | tetrasomy 18p |
How many people are affected by tetrasomy 18p ? | Tetrasomy 18p is a rare disorder. It is known to affect about 250 families worldwide. | tetrasomy 18p |
What are the genetic changes related to tetrasomy 18p ? | Tetrasomy 18p results from the presence of an abnormal extra chromosome, called an isochromosome 18p, in each cell. An isochromosome is a chromosome with two identical arms. Normal chromosomes have one long (q) arm and one short (p) arm, but isochromosomes have either two q arms or two p arms. Isochromosome 18p is a version of chromosome 18 made up of two p arms. Cells normally have two copies of each chromosome, one inherited from each parent. In people with tetrasomy 18p, cells have the usual two copies of chromosome 18 plus an isochromosome 18p. As a result, each cell has four copies of the short arm of chromosome 18. (The word "tetrasomy" is derived from "tetra," the Greek word for "four.") The extra genetic material from the isochromosome disrupts the normal course of development, causing the characteristic features of this disorder. | tetrasomy 18p |
Is tetrasomy 18p inherited ? | Tetrasomy 18p is usually not inherited. The chromosomal change responsible for the disorder typically occurs as a random event during the formation of reproductive cells (eggs or sperm) in a parent of the affected individual, usually the mother. Most affected individuals have no history of the disorder in their family. However, rare inherited cases of tetrasomy 18p have been reported. | tetrasomy 18p |
What are the treatments for tetrasomy 18p ? | These resources address the diagnosis or management of tetrasomy 18p: - Chromosome 18 Clinical Research Center, University of Texas Health Science Center at San Antonio - Genetic Testing Registry: Chromosome 18, tetrasomy 18p 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 | tetrasomy 18p |
What is (are) heterotaxy syndrome ? | Heterotaxy syndrome is a condition in which the internal organs are abnormally arranged in the chest and abdomen. The term "heterotaxy" is from the Greek words "heteros," meaning "other than," and "taxis," meaning "arrangement." Individuals with this condition have complex birth defects affecting the heart, lungs, liver, spleen, intestines, and other organs. In the normal body, most of the organs in the chest and abdomen have a particular location on the right or left side. For example, the heart, spleen, and pancreas are on the left side of the body, and most of the liver is on the right. This normal arrangement of the organs is known as "situs solitus." Rarely, the orientation of the internal organs is completely flipped from right to left, a situation known as "situs inversus." This mirror-image orientation usually does not cause any health problems, unless it occurs as part of a syndrome affecting other parts of the body. Heterotaxy syndrome is an arrangement of internal organs somewhere between situs solitus and situs inversus; this condition is also known as "situs ambiguus." Unlike situs inversus, the abnormal arrangement of organs in heterotaxy syndrome often causes serious health problems. Heterotaxy syndrome alters the structure of the heart, including the attachment of the large blood vessels that carry blood to and from the rest of the body. It can also affect the structure of the lungs, such as the number of lobes in each lung and the length of the tubes (called bronchi) that lead from the windpipe to the lungs. In the abdomen, the condition can cause a person to have no spleen (asplenia) or multiple small, poorly functioning spleens (polysplenia). The liver may lie across the middle of the body instead of being in its normal position to the right of the stomach. Some affected individuals also have intestinal malrotation, which is an abnormal twisting of the intestines that occurs in the early stages of development before birth. Depending on the organs involved, signs and symptoms of heterotaxy syndrome can include a bluish appearance of the skin or lips (cyanosis, which is due to a shortage of oxygen), breathing difficulties, an increased risk of infections, and problems with digesting food. The most serious complications are generally caused by critical congenital heart disease, a group of complex heart defects that are present from birth. Biliary atresia, a problem with the bile ducts in the liver, can also cause severe health problems in infancy. Heterotaxy syndrome is often life-threatening in infancy or childhood, even with treatment, although its severity depends on the specific abnormalities involved. | heterotaxy syndrome |
How many people are affected by heterotaxy syndrome ? | The prevalence of heterotaxy syndrome is estimated to be 1 in 10,000 people worldwide. However, researchers suspect that the condition is underdiagnosed, and so it may actually be more common than this. Heterotaxy syndrome accounts for approximately 3 percent of all congenital heart defects. For reasons that are unknown, the condition appears to be more common in Asian populations than in North America and Europe. Recent studies report that in the United States, the condition occurs more frequently in children born to black or Hispanic mothers than in children born to white mothers. | heterotaxy syndrome |
What are the genetic changes related to heterotaxy syndrome ? | Heterotaxy syndrome can be caused by mutations in many different genes. The proteins produced from most of these genes play roles in determining which structures should be on the right side of the body and which should be on the left, a process known as establishing left-right asymmetry. This process occurs during the earliest stages of embryonic development. Dozens of genes are probably involved in establishing left-right asymmetry; mutations in at least 20 of these genes have been identified in people with heterotaxy syndrome. In some cases, heterotaxy syndrome is caused by mutations in genes whose involvement in determining left-right asymmetry is unknown. Rarely, chromosomal changes such as insertions, deletions, duplications, and other rearrangements of genetic material have been associated with this condition. Heterotaxy syndrome can occur by itself, or it can be a feature of other genetic syndromes that have additional signs and symptoms. For example, at least 12 percent of people with a condition called primary ciliary dyskinesia have heterotaxy syndrome. In addition to abnormally positioned internal organs, primary ciliary dyskinesia is characterized by chronic respiratory tract infections and an inability to have children (infertility). The signs and symptoms of this condition are caused by abnormal cilia, which are microscopic, finger-like projections that stick out from the surface of cells. It appears that cilia play a critical role in establishing left-right asymmetry before birth. Studies suggest that certain factors affecting a woman during pregnancy may also contribute to the risk of heterotaxy syndrome in her child. These include diabetes mellitus; smoking; and exposure to hair dyes, cocaine, and certain laboratory chemicals. Some people with heterotaxy syndrome have no identified gene mutations or other risk factors. In these cases, the cause of the condition is unknown. | heterotaxy syndrome |
Is heterotaxy syndrome inherited ? | Most often, heterotaxy syndrome is sporadic, meaning that only one person in a family is affected. However, about 10 percent of people with heterotaxy syndrome have a close relative (such as a parent or sibling) who has a congenital heart defect without other apparent features of heterotaxy syndrome. Isolated congenital heart defects and heterotaxy syndrome may represent a range of signs and symptoms that can result from a particular genetic mutation; this situation is known as variable expressivity. It is also possible that different genetic and environmental factors combine to produce isolated congenital heart defects in some family members and heterotaxy syndrome in others. When heterotaxy syndrome runs in families, it can have an autosomal dominant, autosomal recessive, or X-linked pattern of inheritance, depending on which gene is involved. Autosomal dominant inheritance means that one copy of the altered gene in each cell is sufficient to cause the disorder. Autosomal recessive inheritance means that both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. In X-linked inheritance, the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. When heterotaxy syndrome occurs as a feature of primary ciliary dyskinesia, it has an autosomal recessive pattern of inheritance. | heterotaxy syndrome |
What are the treatments for heterotaxy syndrome ? | These resources address the diagnosis or management of heterotaxy syndrome: - Boston Children's Hospital: Tests for Heterotaxy Syndrome - Gene Review: Gene Review: Primary Ciliary Dyskinesia - Genetic Testing Registry: Atrioventricular septal defect, partial, with heterotaxy syndrome - Genetic Testing Registry: Heterotaxy 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 | heterotaxy syndrome |
What is (are) Niemann-Pick disease ? | Niemann-Pick disease is a condition that affects many body systems. It has a wide range of symptoms that vary in severity. Niemann-Pick disease is divided into four main types: type A, type B, type C1, and type C2. These types are classified on the basis of genetic cause and the signs and symptoms of the condition. Infants with Niemann-Pick disease type A usually develop an enlarged liver and spleen (hepatosplenomegaly) by age 3 months and fail to gain weight and grow at the expected rate (failure to thrive). The affected children develop normally until around age 1 year when they experience a progressive loss of mental abilities and movement (psychomotor regression). Children with Niemann-Pick disease type A also develop widespread lung damage (interstitial lung disease) that can cause recurrent lung infections and eventually lead to respiratory failure. All affected children have an eye abnormality called a cherry-red spot, which can be identified with an eye examination. Children with Niemann-Pick disease type A generally do not survive past early childhood. Niemann-Pick disease type B usually presents in mid-childhood. The signs and symptoms of this type are similar to type A, but not as severe. People with Niemann-Pick disease type B often have hepatosplenomegaly, recurrent lung infections, and a low number of platelets in the blood (thrombocytopenia). They also have short stature and slowed mineralization of bone (delayed bone age). About one-third of affected individuals have the cherry-red spot eye abnormality or neurological impairment. People with Niemann-Pick disease type B usually survive into adulthood. The signs and symptoms of Niemann-Pick disease types C1 and C2 are very similar; these types differ only in their genetic cause. Niemann-Pick disease types C1 and C2 usually become apparent in childhood, although signs and symptoms can develop at any time. People with these types usually develop difficulty coordinating movements (ataxia), an inability to move the eyes vertically (vertical supranuclear gaze palsy), poor muscle tone (dystonia), severe liver disease, and interstitial lung disease. Individuals with Niemann-Pick disease types C1 and C2 have problems with speech and swallowing that worsen over time, eventually interfering with feeding. Affected individuals often experience progressive decline in intellectual function and about one-third have seizures. People with these types may survive into adulthood. | Niemann-Pick disease |
How many people are affected by Niemann-Pick disease ? | Niemann-Pick disease types A and B is estimated to affect 1 in 250,000 individuals. Niemann-Pick disease type A occurs more frequently among individuals of Ashkenazi (eastern and central European) Jewish descent than in the general population. The incidence within the Ashkenazi population is approximately 1 in 40,000 individuals. Combined, Niemann-Pick disease types C1 and C2 are estimated to affect 1 in 150,000 individuals; however, type C1 is by far the more common type, accounting for 95 percent of cases. The disease occurs more frequently in people of French-Acadian descent in Nova Scotia. In Nova Scotia, a population of affected French-Acadians were previously designated as having Niemann-Pick disease type D, however, it was shown that these individuals have mutations in the gene associated with Niemann-Pick disease type C1. | Niemann-Pick disease |
What are the genetic changes related to Niemann-Pick disease ? | Niemann-Pick disease types A and B is caused by mutations in the SMPD1 gene. This gene provides instructions for producing an enzyme called acid sphingomyelinase. This enzyme is found in lysosomes, which are compartments within cells that break down and recycle different types of molecules. Acid sphingomyelinase is responsible for the conversion of a fat (lipid) called sphingomyelin into another type of lipid called ceramide. Mutations in SMPD1 lead to a shortage of acid sphingomyelinase, which results in reduced break down of sphingomyelin, causing this fat to accumulate in cells. This fat buildup causes cells to malfunction and eventually die. Over time, cell loss impairs function of tissues and organs including the brain, lungs, spleen, and liver in people with Niemann-Pick disease types A and B. Mutations in either the NPC1 or NPC2 gene cause Niemann-Pick disease type C. The proteins produced from these genes are involved in the movement of lipids within cells. Mutations in these genes lead to a shortage of functional protein, which prevents movement of cholesterol and other lipids, leading to their accumulation in cells. Because these lipids are not in their proper location in cells, many normal cell functions that require lipids (such as cell membrane formation) are impaired. The accumulation of lipids as well as the cell dysfunction eventually leads to cell death, causing the tissue and organ damage seen in Niemann-Pick disease types C1 and C2. | Niemann-Pick disease |
Is Niemann-Pick disease inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | Niemann-Pick disease |
What are the treatments for Niemann-Pick disease ? | These resources address the diagnosis or management of Niemann-Pick disease: - Baby's First Test - Gene Review: Gene Review: Acid Sphingomyelinase Deficiency - Gene Review: Gene Review: Niemann-Pick Disease Type C - Genetic Testing Registry: Niemann-Pick disease type C1 - Genetic Testing Registry: Niemann-Pick disease type C2 - Genetic Testing Registry: Niemann-Pick disease, type A - Genetic Testing Registry: Niemann-Pick disease, type B - Genetic Testing Registry: Niemann-Pick disease, type C - Genetic Testing Registry: Niemann-Pick disease, type D - Genetic Testing Registry: Niemann-pick disease, intermediate, protracted neurovisceral - Genetic Testing Registry: Sphingomyelin/cholesterol lipidosis - MedlinePlus Encyclopedia: Niemann-Pick Disease These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Niemann-Pick disease |
What is (are) Emanuel syndrome ? | Emanuel syndrome is a chromosomal disorder that disrupts normal development and affects many parts of the body. Infants with Emanuel syndrome have weak muscle tone (hypotonia) and fail to gain weight and grow at the expected rate (failure to thrive). Their development is significantly delayed, and most affected individuals have severe to profound intellectual disability. Other features of Emanuel syndrome include an unusually small head (microcephaly), distinctive facial features, and a small lower jaw (micrognathia). Ear abnormalities are common, including small holes in the skin just in front of the ears (preauricular pits or sinuses). About half of all affected infants are born with an opening in the roof of the mouth (cleft palate) or a high arched palate. Males with Emanuel syndrome often have genital abnormalities. Additional signs of this condition can include heart defects and absent or unusually small (hypoplastic) kidneys; these problems can be life-threatening in infancy or childhood. | Emanuel syndrome |
How many people are affected by Emanuel syndrome ? | Emanuel syndrome is a rare disorder; its prevalence is unknown. More than 100 individuals with this condition have been reported. | Emanuel syndrome |
What are the genetic changes related to Emanuel syndrome ? | Emanuel syndrome is caused by the presence of extra genetic material from chromosome 11 and chromosome 22 in each cell. In addition to the usual 46 chromosomes, people with Emanuel syndrome have an extra (supernumerary) chromosome consisting of a piece of chromosome 11 attached to a piece of chromosome 22. The extra chromosome is known as a derivative 22 or der(22) chromosome. As a result of the extra chromosome, people with Emanuel syndrome have three copies of some genes in each cell instead of the usual two copies. The excess genetic material disrupts the normal course of development, leading to the characteristic signs and symptoms of this disorder. Researchers are working to determine which genes are included on the der(22) chromosome and what role these genes play in development. | Emanuel syndrome |
Is Emanuel syndrome inherited ? | Almost everyone with Emanuel syndrome inherits the der(22) chromosome from an unaffected parent. The parent carries a chromosomal rearrangement between chromosomes 11 and 22 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, translocations can become unbalanced as they are passed to the next generation. Individuals with Emanuel syndrome inherit an unbalanced translocation between chromosomes 11 and 22 that introduces extra genetic material in the form of the der(22) chromosome. This extra genetic material causes birth defects and the other health problems characteristic of this disorder. | Emanuel syndrome |
What are the treatments for Emanuel syndrome ? | These resources address the diagnosis or management of Emanuel syndrome: - Gene Review: Gene Review: Emanuel Syndrome - Genetic Testing Registry: Emanuel syndrome - MedlinePlus Encyclopedia: Cleft Lip and Palate - MedlinePlus Encyclopedia: Microcephaly - MedlinePlus Encyclopedia: Preauricular Tag or Pit 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 | Emanuel syndrome |
What is (are) actin-accumulation myopathy ? | Actin-accumulation myopathy is a disorder that primarily affects skeletal muscles, which are muscles that the body uses for movement. People with actin-accumulation myopathy have severe muscle weakness (myopathy) and poor muscle tone (hypotonia) throughout the body. Signs and symptoms of this condition are apparent in infancy and include feeding and swallowing difficulties, a weak cry, and difficulty with controlling head movements. Affected babies are sometimes described as "floppy" and may be unable to move on their own. The severe muscle weakness that occurs in actin-accumulation myopathy also affects the muscles used for breathing. Individuals with this disorder may take shallow breaths (hypoventilate), especially during sleep, resulting in a shortage of oxygen and a buildup of carbon dioxide in the blood. Frequent respiratory infections and life-threatening breathing difficulties can occur. Because of the respiratory problems, most affected individuals do not survive past infancy. Those who do survive have delayed development of motor skills such as sitting, crawling, standing, and walking. The name actin-accumulation myopathy derives from characteristic accumulations in muscle cells of filaments composed of a protein called actin. These filaments can be seen when muscle tissue is viewed under a microscope. | actin-accumulation myopathy |
How many people are affected by actin-accumulation myopathy ? | Actin-accumulation myopathy is a rare disorder that has been identified in only a small number of individuals. Its exact prevalence is unknown. | actin-accumulation myopathy |
What are the genetic changes related to actin-accumulation myopathy ? | Actin-accumulation myopathy is caused by a mutation in the ACTA1 gene. This gene provides instructions for making a protein called skeletal alpha ()-actin, which is a member of the actin protein family found in skeletal muscles. Actin proteins are important for cell movement and the tensing of muscle fibers (muscle contraction). Thin filaments made up of actin molecules and thick filaments made up of another protein called myosin are the primary components of muscle fibers and are important for muscle contraction. Attachment (binding) and release of the overlapping thick and thin filaments allows them to move relative to each other so that the muscles can contract. ACTA1 gene mutations that cause actin-accumulation myopathy may affect the way the skeletal -actin protein binds to ATP. ATP is a molecule that supplies energy for cells' activities, and is important in the formation of thin filaments from individual actin molecules. Dysfunctional actin-ATP binding may result in abnormal thin filament formation and impair muscle contraction, leading to muscle weakness and the other signs and symptoms of actin-accumulation myopathy. In some people with actin-accumulation myopathy, no ACTA1 gene mutations have been identified. The cause of the disorder in these individuals is unknown. | actin-accumulation myopathy |
Is actin-accumulation myopathy inherited ? | Actin-accumulation myopathy is an autosomal dominant condition, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most cases are not inherited; they result from new mutations in the gene and occur in people with no history of the disorder in their family. | actin-accumulation myopathy |
What are the treatments for actin-accumulation myopathy ? | These resources address the diagnosis or management of actin-accumulation myopathy: - Genetic Testing Registry: Nemaline myopathy 3 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | actin-accumulation myopathy |
What is (are) tarsal-carpal coalition syndrome ? | Tarsal-carpal coalition syndrome is a rare, inherited bone disorder that affects primarily the hands and feet. Several individual bones make up each wrist (carpal bones) and ankle (tarsal bones). In tarsal-carpal coalition syndrome, the carpal bones fuse together, as do the tarsal bones, which causes stiffness and immobility of the hands and feet. Symptoms of the condition can become apparent in infancy, and they worsen with age. The severity of the symptoms can vary, even among members of the same family. In this condition, fusion at the joints between the bones that make up each finger and toe (symphalangism) can also occur. Consequently, the fingers and toes become stiff and difficult to bend. Stiffness of the pinky fingers and toes (fifth digits) is usually noticeable first. The joints at the base of the pinky fingers and toes fuse first, and slowly, the other joints along the length of these digits may also be affected. Progressively, the bones in the fourth, third, and second digits (the ring finger, middle finger, and forefinger, and the corresponding toes) become fused. The thumb and big toe are usually not involved. Affected individuals have increasing trouble forming a fist, and walking often becomes painful and difficult. Occasionally, there is also fusion of bones in the upper and lower arm at the elbow joint (humeroradial fusion). Less common features of tarsal-carpal coalition syndrome include short stature or the development of hearing loss. | tarsal-carpal coalition syndrome |
How many people are affected by tarsal-carpal coalition syndrome ? | This condition is very rare; however, the exact prevalence is unknown. | tarsal-carpal coalition syndrome |
What are the genetic changes related to tarsal-carpal coalition syndrome ? | Tarsal-carpal coalition syndrome is caused by mutations in the NOG gene, which provides instructions for making a protein called noggin. This protein plays an important role in proper bone and joint development by blocking (inhibiting) signals that stimulate bone formation. The noggin protein attaches (binds) to proteins called bone morphogenetic proteins (BMPs), which keeps the BMPs from triggering signals for the development of bone. NOG gene mutations that cause tarsal-carpal coalition syndrome reduce the amount of functional noggin protein. With decreased noggin function, BMPs abnormally stimulate bone formation in joint areas, where there should be no bone, causing the bone fusions seen in people with tarsal-carpal coalition syndrome. Mutations in the NOG gene are involved in several disorders with overlapping signs and symptoms. Because of a shared genetic cause and overlapping features, researchers have suggested that these conditions, including tarsal-carpal coalition syndrome, represent a spectrum of related conditions referred to as NOG-related-symphalangism spectrum disorder (NOG-SSD). | tarsal-carpal coalition syndrome |
Is tarsal-carpal coalition 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. | tarsal-carpal coalition syndrome |
What are the treatments for tarsal-carpal coalition syndrome ? | These resources address the diagnosis or management of tarsal-carpal coalition syndrome: - Foot Health Facts: Tarsal Coalition - Genetic Testing Registry: Tarsal carpal coalition 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 | tarsal-carpal coalition syndrome |
What is (are) carbamoyl phosphate synthetase I deficiency ? | Carbamoyl phosphate synthetase I deficiency is an inherited disorder that causes ammonia to accumulate in the blood (hyperammonemia). Ammonia, which is formed when proteins are broken down in the body, is toxic if the levels become too high. The brain is especially sensitive to the effects of excess ammonia. In the first few days of life, infants with carbamoyl phosphate synthetase I deficiency typically exhibit the effects of hyperammonemia, which may include unusual sleepiness, poorly regulated breathing rate or body temperature, unwillingness to feed, vomiting after feeding, unusual body movements, seizures, or coma. Affected individuals who survive the newborn period may experience recurrence of these symptoms if diet is not carefully managed or if they experience infections or other stressors. They may also have delayed development and intellectual disability. In some people with carbamoyl phosphate synthetase I deficiency, signs and symptoms may be less severe and appear later in life. | carbamoyl phosphate synthetase I deficiency |
How many people are affected by carbamoyl phosphate synthetase I deficiency ? | Carbamoyl phosphate synthetase I deficiency is a rare disorder; its overall incidence is unknown. Researchers in Japan have estimated that it occurs in 1 in 800,000 newborns in that country. | carbamoyl phosphate synthetase I deficiency |
What are the genetic changes related to carbamoyl phosphate synthetase I deficiency ? | Mutations in the CPS1 gene cause carbamoyl phosphate synthetase I deficiency. The CPS1 gene provides instructions for making the enzyme carbamoyl phosphate synthetase I. This enzyme participates in the urea cycle, which is a sequence of biochemical reactions that occurs in liver cells. The urea cycle processes excess nitrogen, generated when protein is broken down by the body, to make a compound called urea that is excreted by the kidneys. The specific role of the carbamoyl phosphate synthetase I enzyme is to control the first step of the urea cycle, a reaction in which excess nitrogen compounds are incorporated into the cycle to be processed. Carbamoyl phosphate synthetase I deficiency belongs to a class of genetic diseases called urea cycle disorders. In this condition, the carbamoyl phosphate synthetase I enzyme is at low levels (deficient) or absent, and the urea cycle cannot proceed normally. As a result, nitrogen accumulates in the bloodstream in the form of toxic ammonia instead of being converted to less toxic urea and excreted. Ammonia is especially damaging to the brain, and excess ammonia causes neurological problems and other signs and symptoms of carbamoyl phosphate synthetase I deficiency. | carbamoyl phosphate synthetase I deficiency |
Is carbamoyl phosphate synthetase I deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | carbamoyl phosphate synthetase I deficiency |
What are the treatments for carbamoyl phosphate synthetase I deficiency ? | These resources address the diagnosis or management of carbamoyl phosphate synthetase I deficiency: - Baby's First Test - Gene Review: Gene Review: Urea Cycle Disorders Overview - Genetic Testing Registry: Congenital hyperammonemia, type I - MedlinePlus Encyclopedia: Hereditary Urea Cycle Abnormality These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | carbamoyl phosphate synthetase I deficiency |
What is (are) Camurati-Engelmann disease ? | Camurati-Engelmann disease is a condition that mainly affects the bones. People with this disease have increased bone density, particularly affecting the long bones of the arms and legs. In some cases, the skull and hip bones are also affected. The thickened bones can lead to pain in the arms and legs, a waddling walk, muscle weakness, and extreme tiredness. An increase in the density of the skull results in increased pressure on the brain and can cause a variety of neurological problems, including headaches, hearing loss, vision problems, dizziness (vertigo), ringing in the ears (tinnitus), and facial paralysis. The added pressure that thickened bones put on the muscular and skeletal systems can cause abnormal curvature of the spine (scoliosis), joint deformities (contractures), knock knees, and flat feet (pes planus). Other features of Camurati-Engelmann disease include abnormally long limbs in proportion to height, a decrease in muscle mass and body fat, and delayed puberty. The age at which affected individuals first experience symptoms varies greatly; however, most people with this condition develop pain or weakness by adolescence. In some instances, people have the gene mutation that causes Camurati-Engelmann disease but never develop the characteristic features of this condition. | Camurati-Engelmann disease |
How many people are affected by Camurati-Engelmann disease ? | The prevalence of Camurati-Engelmann disease is unknown. Approximately 200 cases have been reported worldwide. | Camurati-Engelmann disease |
What are the genetic changes related to Camurati-Engelmann disease ? | Mutations in the TGFB1 gene cause Camurati-Engelmann disease. The TGFB1 gene provides instructions for producing a protein called transforming growth factor beta-1 (TGF-1). The TGF-1 protein helps control the growth and division (proliferation) of cells, the process by which cells mature to carry out specific functions (differentiation), cell movement (motility), and the self-destruction of cells (apoptosis). The TGF-1 protein is found throughout the body and plays a role in development before birth, the formation of blood vessels, the regulation of muscle tissue and body fat development, wound healing, and immune system function. TGF-1 is particularly abundant in tissues that make up the skeleton, where it helps regulate bone growth, and in the intricate lattice that forms in the spaces between cells (the extracellular matrix). Within cells, the TGF-1 protein is turned off (inactive) until it receives a chemical signal to become active. The TGFB1 gene mutations that cause Camurati-Engelmann disease result in the production of a TGF-1 protein that is always turned on (active). Overactive TGF-1 proteins lead to increased bone density and decreased body fat and muscle tissue, contributing to the signs and symptoms of Camurati-Engelmann disease. Some individuals with Camurati-Engelmann disease do not have identified mutations in the TGFB1 gene. In these cases, the cause of the condition is unknown. | Camurati-Engelmann disease |
Is Camurati-Engelmann disease 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. | Camurati-Engelmann disease |
What are the treatments for Camurati-Engelmann disease ? | These resources address the diagnosis or management of Camurati-Engelmann disease: - Gene Review: Gene Review: Camurati-Engelmann Disease - Genetic Testing Registry: Diaphyseal dysplasia These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Camurati-Engelmann disease |
What is (are) prolidase deficiency ? | Prolidase deficiency is a disorder that causes a wide variety of symptoms. The disorder typically becomes apparent during infancy. Affected individuals may have enlargement of the spleen (splenomegaly); in some cases, both the spleen and liver are enlarged (hepatosplenomegaly). Diarrhea, vomiting, and dehydration may also occur. People with prolidase deficiency are susceptible to severe infections of the skin or ears, or potentially life-threatening respiratory tract infections. Some individuals with prolidase deficiency have chronic lung disease. Characteristic facial features in people with prolidase deficiency include prominent eyes that are widely spaced (hypertelorism), a high forehead, a flat bridge of the nose, and a very small lower jaw and chin (micrognathia). Affected children may experience delayed development, and about 75 percent of people with prolidase deficiency have intellectual disability that may range from mild to severe. People with prolidase deficiency often develop skin lesions, especially on their hands, feet, lower legs, and face. The severity of the skin involvement, which usually begins during childhood, may range from a mild rash to severe skin ulcers. Skin ulcers, especially on the legs, may not heal completely, resulting in complications including infection and amputation. The severity of symptoms in prolidase deficiency varies greatly among affected individuals. Some people with this disorder do not have any symptoms. In these individuals the condition can be detected by laboratory tests such as newborn screening tests or tests offered to relatives of affected individuals. | prolidase deficiency |
How many people are affected by prolidase deficiency ? | Prolidase deficiency is a rare disorder. Approximately 70 individuals with this disorder have been documented in the medical literature, and researchers have estimated that the condition occurs in approximately 1 in 1 million to 1 in 2 million newborns. It is more common in certain areas in northern Israel, both among members of a religious minority called the Druze and in nearby Arab Moslem populations. | prolidase deficiency |
What are the genetic changes related to prolidase deficiency ? | Prolidase deficiency is caused by mutations in the PEPD gene. This gene provides instructions for making the enzyme prolidase, also called peptidase D. Prolidase helps divide certain dipeptides, which are molecules composed of two protein building blocks (amino acids). Specifically, prolidase divides dipeptides containing the amino acids proline or hydroxyproline. By freeing these amino acids, prolidase helps make them available for use in producing proteins that the body needs. Prolidase is also involved in the final step of the breakdown of some proteins obtained through the diet and proteins that are no longer needed in the body. Prolidase is particularly important in the breakdown of collagens, a family of proteins that are rich in proline and hydroxyproline. Collagens are an important part of the extracellular matrix, which is the lattice of proteins and other molecules outside the cell. The extracellular matrix strengthens and supports connective tissues, such as skin, bone, cartilage, tendons, and ligaments. Collagen breakdown occurs during the maintenance (remodeling) of the extracellular matrix. PEPD gene mutations that cause prolidase deficiency result in the loss of prolidase enzyme activity. It is not well understood how the absence of prolidase activity causes the various signs and symptoms of prolidase deficiency. Researchers have suggested that accumulation of dipeptides that have not been broken down may lead to cell death. When cells die, their contents are released into the surrounding tissue, which could cause inflammation and lead to the skin problems seen in prolidase deficiency. Impaired collagen breakdown during remodeling of the extracellular matrix may also contribute to the skin problems. The intellectual disability that occurs in prolidase deficiency might result from problems in processing neuropeptides, which are brain signaling proteins that are rich in proline. It is unclear how absence of prolidase activity results in the other features of prolidase deficiency. | prolidase deficiency |
Is prolidase 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. | prolidase deficiency |
What are the treatments for prolidase deficiency ? | These resources address the diagnosis or management of prolidase deficiency: - Gene Review: Gene Review: Prolidase Deficiency - Genetic Testing Registry: Prolidase 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 | prolidase deficiency |
What is (are) childhood myocerebrohepatopathy spectrum ? | Childhood myocerebrohepatopathy spectrum, commonly called MCHS, is part of a group of conditions called the POLG-related disorders. The conditions in this group feature a range of similar signs and symptoms involving muscle-, nerve-, and brain-related functions. MCHS typically becomes apparent in children from a few months to 3 years old. People with this condition usually have problems with their muscles (myo-), brain (cerebro-), and liver (hepato-). Common signs and symptoms of MCHS include muscle weakness (myopathy), developmental delay or a deterioration of intellectual function, and liver disease. Another possible sign of this condition is a toxic buildup of lactic acid in the body (lactic acidosis). Often, affected children are unable to gain weight and grow at the expected rate (failure to thrive). Additional signs and symptoms of MCHS can include a form of kidney disease called renal tubular acidosis, inflammation of the pancreas (pancreatitis), recurrent episodes of nausea and vomiting (cyclic vomiting), or hearing loss. | childhood myocerebrohepatopathy spectrum |
How many people are affected by childhood myocerebrohepatopathy spectrum ? | The prevalence of childhood myocerebrohepatopathy spectrum is unknown. | childhood myocerebrohepatopathy spectrum |
What are the genetic changes related to childhood myocerebrohepatopathy spectrum ? | MCHS is caused by mutations in the POLG gene. This gene provides instructions for making one part, the alpha subunit, of a protein called polymerase gamma (pol ). Pol functions in mitochondria, which are structures within cells that use oxygen to convert the energy from food into a form cells can use. Mitochondria each contain a small amount of DNA, known as mitochondrial DNA (mtDNA), which is essential for the normal function of these structures. Pol "reads" sequences of mtDNA and uses them as templates to produce new copies of mtDNA in a process called DNA replication. Most POLG gene mutations change single protein building blocks (amino acids) in the alpha subunit of pol . These changes result in a mutated pol that has a reduced ability to replicate DNA. Although the mechanism is unknown, mutations in the POLG gene often result in fewer copies of mtDNA (mtDNA depletion), particularly in muscle, brain, or liver cells. MtDNA depletion causes a decrease in cellular energy, which could account for the signs and symptoms of MCHS. | childhood myocerebrohepatopathy spectrum |
Is childhood myocerebrohepatopathy spectrum 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. | childhood myocerebrohepatopathy spectrum |
What are the treatments for childhood myocerebrohepatopathy spectrum ? | These resources address the diagnosis or management of MCHS: - Gene Review: Gene Review: POLG-Related Disorders - United Mitochondrial Disease Foundation: Diagnosis of Mitochondrial 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 | childhood myocerebrohepatopathy spectrum |
What is (are) familial paroxysmal kinesigenic dyskinesia ? | Familial paroxysmal kinesigenic dyskinesia is a disorder characterized by episodes of abnormal movement that range from mild to severe. In the condition name, the word paroxysmal indicates that the abnormal movements come and go over time, kinesigenic means that episodes are triggered by movement, and dyskinesia refers to involuntary movement of the body. People with familial paroxysmal kinesigenic dyskinesia experience episodes of irregular jerking or shaking movements that are induced by sudden motion, such as standing up quickly or being startled. An episode may involve slow, prolonged muscle contractions (dystonia); small, fast, "dance-like" motions (chorea); writhing movements of the limbs (athetosis); or, rarely, flailing movements of the limbs (ballismus). Familial paroxysmal kinesigenic dyskinesia may affect one or both sides of the body. The type of abnormal movement varies among affected individuals, even among members of the same family. In many people with familial paroxysmal kinesigenic dyskinesia, a pattern of symptoms called an aura immediately precedes the episode. The aura is often described as a crawling or tingling sensation in the affected body part. Individuals with this condition do not lose consciousness during an episode and do not experience any symptoms between episodes. Individuals with familial paroxysmal kinesigenic dyskinesia usually begin to show signs and symptoms of the disorder during childhood or adolescence. Episodes typically last less than five minutes, and the frequency of episodes ranges from one per month to 100 per day. In most affected individuals, episodes occur less often with age. In some people with familial paroxysmal kinesigenic dyskinesia the disorder begins in infancy with recurring seizures called benign infantile convulsions. These seizures usually develop in the first year of life and stop by age 3. When benign infantile convulsions are associated with familial paroxysmal kinesigenic dyskinesia, the condition is known as infantile convulsions and choreoathetosis (ICCA). In families with ICCA, some individuals develop only benign infantile convulsions, some have only familial paroxysmal kinesigenic dyskinesia, and others develop both. | familial paroxysmal kinesigenic dyskinesia |
How many people are affected by familial paroxysmal kinesigenic dyskinesia ? | Familial paroxysmal kinesigenic dyskinesia is estimated to occur in 1 in 150,000 individuals. For unknown reasons, this condition affects more males than females. | familial paroxysmal kinesigenic dyskinesia |
What are the genetic changes related to familial paroxysmal kinesigenic dyskinesia ? | Familial paroxysmal kinesigenic dyskinesia can be caused by mutations in the PRRT2 gene. The function of the protein produced from this gene is unknown, although it is thought to be involved in the development and function of the brain. Studies suggest that the PRRT2 protein interacts with a protein that helps control signaling between nerve cells (neurons). It is thought that PRRT2 gene mutations, which reduce the amount of PRRT2 protein, lead to abnormal neuronal signaling. Altered neuronal activity could underlie the movement problems associated with familial paroxysmal kinesigenic dyskinesia. Not everyone with this condition has a mutation in the PRRT2 gene. When no PRRT2 gene mutations are found, the cause of the condition is unknown. | familial paroxysmal kinesigenic dyskinesia |
Is familial paroxysmal kinesigenic dyskinesia inherited ? | This condition 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. In most cases, an affected person has one parent with the condition. | familial paroxysmal kinesigenic dyskinesia |
What are the treatments for familial paroxysmal kinesigenic dyskinesia ? | These resources address the diagnosis or management of familial paroxysmal kinesigenic dyskinesia: - Gene Review: Gene Review: Familial Paroxysmal Kinesigenic Dyskinesia - Genetic Testing Registry: Dystonia 10 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 paroxysmal kinesigenic dyskinesia |
What is (are) multiple cutaneous and mucosal venous malformations ? | Multiple cutaneous and mucosal venous malformations (also known as VMCM) are bluish patches (lesions) on the skin (cutaneous) and the mucous membranes, such as the lining of the mouth and nose. These lesions represent areas where the underlying veins and other blood vessels did not develop properly (venous malformations). The lesions can be painful, especially when they extend from the skin into the muscles and joints, or when a calcium deposit forms within the lesion causing inflammation and swelling. Most people with VMCM are born with at least one venous malformation. As affected individuals age, the lesions present from birth usually become larger and new lesions often appear. The size, number, and location of venous malformations vary among affected individuals, even among members of the same family. | multiple cutaneous and mucosal venous malformations |
How many people are affected by multiple cutaneous and mucosal venous malformations ? | VMCM appears to be a rare disorder, although its prevalence is unknown. | multiple cutaneous and mucosal venous malformations |
What are the genetic changes related to multiple cutaneous and mucosal venous malformations ? | Mutations in the TEK gene (also called the TIE2 gene) cause VMCM. The TEK gene provides instructions for making a protein called TEK receptor tyrosine kinase. This receptor protein triggers chemical signals needed for forming blood vessels (angiogenesis) and maintaining their structure. This signaling process facilitates communication between two types of cells within the walls of blood vessels, endothelial cells and smooth muscle cells. Communication between these two cell types is necessary to direct angiogenesis and ensure the structure and integrity of blood vessels. TEK gene mutations that cause VMCM result in a TEK receptor that is always turned on (overactive). An overactive TEK receptor is thought to disrupt the communication between endothelial cells and smooth muscle cells. It is unclear how a lack of communication between these cells causes venous malformations. These abnormal blood vessels show a deficiency of smooth muscle cells while endothelial cells are maintained. Venous malformations cause lesions below the surface of the skin or mucous membranes, which are characteristic of VMCM. | multiple cutaneous and mucosal venous malformations |
Is multiple cutaneous and mucosal venous malformations inherited ? | VMCM is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to increase the risk of developing venous malformations. Some gene mutations are acquired during a person's lifetime and are present only in certain cells. These changes, which are not inherited, are called somatic mutations. Researchers have discovered that some VMCM lesions have one inherited and one somatic TEK gene mutation. It is not known if the somatic mutation occurs before or after the venous malformation forms. As lesions are localized and not all veins are malformed, it is thought that the inherited mutation alone is not enough to cause venous malformations. In most cases, an affected person has one parent with the condition. | multiple cutaneous and mucosal venous malformations |
What are the treatments for multiple cutaneous and mucosal venous malformations ? | These resources address the diagnosis or management of VMCM: - Gene Review: Gene Review: Multiple Cutaneous and Mucosal Venous Malformations - Genetic Testing Registry: Multiple Cutaneous and Mucosal Venous Malformations 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 | multiple cutaneous and mucosal venous malformations |
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). | isodicentric chromosome 15 syndrome |
How many people are affected by isodicentric chromosome 15 syndrome ? | Isodicentric chromosome 15 syndrome occurs in about 1 in 30,000 newborns. | isodicentric chromosome 15 syndrome |
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. | isodicentric chromosome 15 syndrome |
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. | isodicentric chromosome 15 syndrome |
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 | isodicentric chromosome 15 syndrome |
Subsets and Splits