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genetic changes | What are the genetic changes related to familial idiopathic basal ganglia calcification ? | Mutations in the SLC20A2 gene cause nearly half of all cases of FIBGC. A small percentage of cases are caused by mutations in the PDGFRB gene. Other cases of FIBGC appear to be associated with changes in chromosomes 2, 7, 9, and 14, although specific genes have yet to be identified. These findings suggest that multiple genes are involved in this condition. The SLC20A2 gene provides instructions for making a protein called sodium-dependent phosphate transporter 2 (PiT-2). This protein plays a major role in regulating phosphate levels within the body (phosphate homeostasis) by transporting phosphate across cell membranes. The SLC20A2 gene mutations that cause FIBGC lead to the production of a PiT-2 protein that cannot effectively transport phosphate into cells. As a result, phosphate levels in the bloodstream rise. In the brain, the excess phosphate combines with calcium and forms deposits. The PDGFRB gene provides instructions for making a protein that plays a role in turning on (activating) signaling pathways that control many cell processes. It is unclear how PDGFRB gene mutations cause FIBGC. Mutations may alter signaling within cells that line blood vessels in the brain, causing them to take in excess calcium, and leading to calcification of the lining of these blood vessels. Alternatively, changes in the PDGFRB protein could alter phosphate transport signaling pathways, causing an increase in phosphate levels and the formation of calcium deposits. Researchers suggest that calcium deposits lead to the characteristic features of FIBGC by interrupting signaling pathways in various parts of the brain. Calcium deposits may disrupt the pathways that connect the basal ganglia to other areas of the brain, particularly the frontal lobes. These areas at the front of the brain are involved in reasoning, planning, judgment, and problem-solving. The regions of the brain that regulate social behavior, mood, and motivation may also be affected. Research has shown that people with significant calcification tend to have more signs and symptoms of FIBGC than people with little or no calcification. However, this association does not apply to all people with FIBGC. |
inheritance | Is familial idiopathic basal ganglia calcification inherited ? | FIBGC is inherited in an autosomal dominant pattern. Autosomal dominant inheritance means one copy of an altered SLC20A2 or PDGFRB gene in each cell is sufficient to cause the disorder. This condition appears to follow an autosomal dominant pattern of inheritance when the genetic cause is not known. In most cases, an affected person has one parent with the condition. |
treatment | What are the treatments for familial idiopathic basal ganglia calcification ? | These resources address the diagnosis or management of FIBGC: - Dystonia Medical Research Foundation: Treatments - Gene Review: Gene Review: Primary Familial Brain Calcification - Genetic Testing Registry: Basal ganglia calcification, idiopathic, 2 - Genetic Testing Registry: Basal ganglia calcification, idiopathic, 4 - Genetic Testing Registry: Idiopathic basal ganglia calcification 1 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) familial atrial fibrillation ? | Familial atrial fibrillation is an inherited condition that disrupts the heart's normal rhythm. This condition is characterized by uncoordinated electrical activity in the heart's upper chambers (the atria), which causes the heartbeat to become fast and irregular. If untreated, this abnormal heart rhythm can lead to dizziness, chest pain, a sensation of fluttering or pounding in the chest (palpitations), shortness of breath, or fainting (syncope). Atrial fibrillation also increases the risk of stroke and sudden death. Complications of familial atrial fibrillation can occur at any age, although some people with this heart condition never experience any health problems associated with the disorder. |
frequency | How many people are affected by familial atrial fibrillation ? | Atrial fibrillation is the most common type of sustained abnormal heart rhythm (arrhythmia), affecting more than 3 million people in the United States. The risk of developing this irregular heart rhythm increases with age. The incidence of the familial form of atrial fibrillation is unknown; however, recent studies suggest that up to 30 percent of all people with atrial fibrillation may have a history of the condition in their family. |
genetic changes | What are the genetic changes related to familial atrial fibrillation ? | A small percentage of all cases of familial atrial fibrillation are associated with changes in the KCNE2, KCNJ2, and KCNQ1 genes. These genes provide instructions for making proteins that act as channels across the cell membrane. These channels transport positively charged atoms (ions) of potassium into and out of cells. In heart (cardiac) muscle, the ion channels produced from the KCNE2, KCNJ2, and KCNQ1 genes play critical roles in maintaining the heart's normal rhythm. Mutations in these genes have been identified in only a few families worldwide. These mutations increase the activity of the channels, which changes the flow of potassium ions between cells. This disruption in ion transport alters the way the heart beats, increasing the risk of syncope, stroke, and sudden death. Most cases of atrial fibrillation are not caused by mutations in a single gene. This condition is often related to structural abnormalities of the heart or underlying heart disease. Additional risk factors for atrial fibrillation include high blood pressure (hypertension), diabetes mellitus, a previous stroke, or an accumulation of fatty deposits and scar-like tissue in the lining of the arteries (atherosclerosis). Although most cases of atrial fibrillation are not known to run in families, studies suggest that they may arise partly from genetic risk factors. Researchers are working to determine which genetic changes may influence the risk of atrial fibrillation. |
inheritance | Is familial atrial fibrillation inherited ? | Familial atrial fibrillation appears to be inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. |
treatment | What are the treatments for familial atrial fibrillation ? | These resources address the diagnosis or management of familial atrial fibrillation: - Genetic Testing Registry: Atrial fibrillation, familial, 1 - Genetic Testing Registry: Atrial fibrillation, familial, 2 - Genetic Testing Registry: Atrial fibrillation, familial, 3 - MedlinePlus Encyclopedia: Arrhythmias - MedlinePlus Encyclopedia: Atrial fibrillation/flutter These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) isolated growth hormone deficiency ? | Isolated growth hormone deficiency is a condition caused by a severe shortage or absence of growth hormone. Growth hormone is a protein that is necessary for the normal growth of the body's bones and tissues. Because they do not have enough of this hormone, people with isolated growth hormone deficiency commonly experience a failure to grow at the expected rate and have unusually short stature. This condition is usually apparent by early childhood. There are four types of isolated growth hormone deficiency differentiated by the severity of the condition, the gene involved, and the inheritance pattern. Isolated growth hormone deficiency type IA is caused by an absence of growth hormone and is the most severe of all the types. In people with type IA, growth failure is evident in infancy as affected babies are shorter than normal at birth. People with isolated growth hormone deficiency type IB produce very low levels of growth hormone. As a result, type IB is characterized by short stature, but this growth failure is typically not as severe as in type IA. Growth failure in people with type IB is usually apparent in early to mid-childhood. Individuals with isolated growth hormone deficiency type II have very low levels of growth hormone and short stature that varies in severity. Growth failure in these individuals is usually evident in early to mid-childhood. It is estimated that nearly half of the individuals with type II have underdevelopment of the pituitary gland (pituitary hypoplasia). The pituitary gland is located at the base of the brain and produces many hormones, including growth hormone. Isolated growth hormone deficiency type III is similar to type II in that affected individuals have very low levels of growth hormone and short stature that varies in severity. Growth failure in type III is usually evident in early to mid-childhood. People with type III may also have a weakened immune system and are prone to frequent infections. They produce very few B cells, which are specialized white blood cells that help protect the body against infection (agammaglobulinemia). |
frequency | How many people are affected by isolated growth hormone deficiency ? | The incidence of isolated growth hormone deficiency is estimated to be 1 in 4,000 to 10,000 individuals worldwide. |
genetic changes | What are the genetic changes related to isolated growth hormone deficiency ? | Isolated growth hormone deficiency is caused by mutations in one of at least three genes. Isolated growth hormone deficiency types IA and II are caused by mutations in the GH1 gene. Type IB is caused by mutations in either the GH1 or GHRHR gene. Type III is caused by mutations in the BTK gene. The GH1 gene provides instructions for making the growth hormone protein. Growth hormone is produced in the pituitary gland and plays a major role in promoting the body's growth. Growth hormone also plays a role in various chemical reactions (metabolic processes) in the body. Mutations in the GH1 gene prevent or impair the production of growth hormone. Without sufficient growth hormone, the body fails to grow at its normal rate, resulting in slow growth and short stature as seen in isolated growth hormone deficiency types IA, IB, and II. The GHRHR gene provides instructions for making a protein called the growth hormone releasing hormone receptor. This receptor attaches (binds) to a molecule called growth hormone releasing hormone. The binding of growth hormone releasing hormone to the receptor triggers the production of growth hormone and its release from the pituitary gland. Mutations in the GHRHR gene impair the production or release of growth hormone. The resulting shortage of growth hormone prevents the body from growing at the expected rate. Decreased growth hormone activity due to GHRHR gene mutations is responsible for many cases of isolated growth hormone deficiency type IB. The BTK gene provides instructions for making a protein called Bruton tyrosine kinase (BTK), which is essential for the development and maturation of immune system cells called B cells. The BTK protein transmits important chemical signals that instruct B cells to mature and produce special proteins called antibodies. Antibodies attach to specific foreign particles and germs, marking them for destruction. It is unknown how mutations in the BTK gene contribute to short stature in people with isolated growth hormone deficiency type III. Some people with isolated growth hormone deficiency do not have mutations in the GH1, GHRHR, or BTK genes. In these individuals, the cause of the condition is unknown. When this condition does not have an identified genetic cause, it is known as idiopathic isolated growth hormone deficiency. |
inheritance | Is isolated growth hormone deficiency inherited ? | Isolated growth hormone deficiency can have different inheritance patterns depending on the type of the condition. Isolated growth hormone deficiency types IA and IB are inherited in an autosomal recessive pattern, which means both copies of the GH1 or GHRHR 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. Isolated growth hormone deficiency type II can be inherited in an autosomal dominant pattern, which means a mutation in one copy of the GH1 gene in each cell is sufficient to cause the disorder. This condition can also result from new mutations in the GH1 gene and occur in people with no history of the disorder in their family. Isolated growth hormone deficiency type III, caused by mutations in the BTK gene, is inherited in an X-linked recessive pattern. The BTK gene is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. |
treatment | What are the treatments for isolated growth hormone deficiency ? | These resources address the diagnosis or management of isolated growth hormone deficiency: - Genetic Testing Registry: Ateleiotic dwarfism - Genetic Testing Registry: Autosomal dominant isolated somatotropin deficiency - Genetic Testing Registry: Isolated growth hormone deficiency type 1B - Genetic Testing Registry: X-linked agammaglobulinemia with growth hormone deficiency - MedlinePlus Encyclopedia: Growth Hormone Test These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Alstrm syndrome ? | Alstrm syndrome is a rare condition that affects many body systems. Many of the signs and symptoms of this condition begin in infancy or early childhood, although some appear later in life. Alstrm syndrome is characterized by a progressive loss of vision and hearing, a form of heart disease that enlarges and weakens the heart muscle (dilated cardiomyopathy), obesity, type 2 diabetes mellitus (the most common form of diabetes), and short stature. This disorder can also cause serious or life-threatening medical problems involving the liver, kidneys, bladder, and lungs. Some individuals with Alstrm syndrome have a skin condition called acanthosis nigricans, which causes the skin in body folds and creases to become thick, dark, and velvety. The signs and symptoms of Alstrm syndrome vary in severity, and not all affected individuals have all of the characteristic features of the disorder. |
frequency | How many people are affected by Alstrm syndrome ? | More than 900 people with Alstrm syndrome have been reported worldwide. |
genetic changes | What are the genetic changes related to Alstrm syndrome ? | Mutations in the ALMS1 gene cause Alstrm syndrome. The ALMS1 gene provides instructions for making a protein whose function is unknown. Mutations in this gene probably lead to the production of an abnormally short, nonfunctional version of the ALMS1 protein. This protein is normally present at low levels in most tissues, so a loss of the protein's normal function may help explain why the signs and symptoms of Alstrm syndrome affect many parts of the body. |
inheritance | Is Alstrm syndrome inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for Alstrm syndrome ? | These resources address the diagnosis or management of Alstrm syndrome: - Gene Review: Gene Review: Alstrom Syndrome - Genetic Testing Registry: Alstrom syndrome - MedlinePlus Encyclopedia: Acanthosis Nigricans - MedlinePlus Encyclopedia: Alstrm syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Meige disease ? | Meige disease is a condition that affects the normal function of the lymphatic system. The lymphatic system consists of a network of vessels that transport lymphatic fluid and immune cells throughout the body. Meige disease is characterized by the abnormal transport of lymphatic fluid. When this fluid builds up abnormally, it causes swelling (lymphedema) in the lower limbs. Meige disease is classified as a primary lymphedema, which means it is a form of lymphedema that is not caused by other health conditions. In Meige disease, the lymphatic system abnormalities are present from birth (congenital), although the swelling is not usually apparent until puberty. The swelling often begins in the feet and ankles and progresses up the legs to the knees. Some affected individuals develop non-contagious skin infections called cellulitis or erysipelas in the legs, which can further damage the vessels that carry lymphatic fluid. |
frequency | How many people are affected by Meige disease ? | The prevalence of Meige disease is unknown. Collectively, the many types of primary lymphedema affect an estimated 1 in 100,000 people younger than 20; Meige disease is the most common type of primary lymphedema. For unknown reasons, this condition affects females about three times as often as males. |
genetic changes | What are the genetic changes related to Meige disease ? | The cause of Meige disease is unknown. The condition is thought to be genetic because it tends to run in families, and other forms of primary lymphedema have been found to have a genetic cause. Researchers have studied many genes associated with the lymphatic system; however, no genetic change has been definitively found to cause the signs and symptoms of Meige disease. |
inheritance | Is Meige disease inherited ? | Meige disease appears to 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, although no genes have been associated with Meige disease. People with Meige disease usually have at least one other affected family member. In most cases, an affected person has one parent with the condition. When the condition occurs in only one person in a family, the condition is described as Meige-like disease. |
treatment | What are the treatments for Meige disease ? | These resources address the diagnosis or management of Meige disease: - Genetic Testing Registry: Lymphedema praecox - Johns Hopkins Medicine: Lymphedema Management These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) hand-foot-genital syndrome ? | Hand-foot-genital syndrome is a rare condition that affects the development of the hands and feet, the urinary tract, and the reproductive system. People with this condition have abnormally short thumbs and first (big) toes, small fifth fingers that curve inward (clinodactyly), short feet, and fusion or delayed hardening of bones in the wrists and ankles. The other bones in the arms and legs are normal. Abnormalities of the genitals and urinary tract can vary among affected individuals. Many people with hand-foot-genital syndrome have defects in the ureters, which are tubes that carry urine from each kidney to the bladder, or in the urethra, which carries urine from the bladder to the outside of the body. Recurrent urinary tract infections and an inability to control the flow of urine (urinary incontinence) have been reported. About half of males with this disorder have the urethra opening on the underside of the penis (hypospadias). People with hand-foot-genital syndrome are usually able to have children (fertile). In some affected females, problems in the early development of the uterus can later increase the risk of pregnancy loss, premature labor, and stillbirth. |
frequency | How many people are affected by hand-foot-genital syndrome ? | Hand-foot-genital syndrome is very rare; only a few families with the condition have been reported worldwide. |
genetic changes | What are the genetic changes related to hand-foot-genital syndrome ? | Mutations in the HOXA13 gene cause hand-foot-genital syndrome. The HOXA13 gene provides instructions for producing a protein that plays an important role in development before birth. Specifically, this protein appears to be critical for the formation and development of the limbs (particularly the hands and feet), urinary tract, and reproductive system. Mutations in the HOXA13 gene cause the characteristic features of hand-foot-genital syndrome by disrupting the early development of these structures. Some mutations in the HOXA13 gene result in the production of a nonfunctional version of the HOXA13 protein. Other mutations alter the protein's structure and interfere with its normal function within cells. Mutations that result in an altered but functional HOXA13 protein may cause more severe signs and symptoms than mutations that lead to a nonfunctional HOXA13 protein. |
inheritance | Is hand-foot-genital 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. |
treatment | What are the treatments for hand-foot-genital syndrome ? | These resources address the diagnosis or management of hand-foot-genital syndrome: - Gene Review: Gene Review: Hand-Foot-Genital Syndrome - Genetic Testing Registry: Hand foot uterus syndrome - MedlinePlus Encyclopedia: Hypospadias - MedlinePlus Encyclopedia: Urinary Tract Infection These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Baraitser-Winter syndrome ? | Baraitser-Winter syndrome is a condition that affects the development of many parts of the body, particularly the face and the brain. An unusual facial appearance is the most common characteristic of Baraitser-Winter syndrome. Distinctive facial features can include widely spaced eyes (hypertelorism), large eyelid openings, droopy eyelids (ptosis), high-arched eyebrows, a broad nasal bridge and tip of the nose, a long space between the nose and upper lip (philtrum), full cheeks, and a pointed chin. Structural brain abnormalities are also present in most people with Baraitser-Winter syndrome. These abnormalities are related to impaired neuronal migration, a process by which nerve cells (neurons) move to their proper positions in the developing brain. The most frequent brain abnormality associated with Baraitser-Winter syndrome is pachygyria, which is an area of the brain that has an abnormally smooth surface with fewer folds and grooves. Less commonly, affected individuals have lissencephaly, which is similar to pachygyria but involves the entire brain surface. These structural changes can cause mild to severe intellectual disability, developmental delay, and seizures. Other features of Baraitser-Winter syndrome can include short stature, ear abnormalities and hearing loss, heart defects, presence of an extra (duplicated) thumb, and abnormalities of the kidneys and urinary system. Some affected individuals have limited movement of large joints, such as the elbows and knees, which may be present at birth or develop over time. Rarely, people with Baraitser-Winter syndrome have involuntary muscle tensing (dystonia). |
frequency | How many people are affected by Baraitser-Winter syndrome ? | Baraitser-Winter syndrome is a rare condition. Fewer than 50 cases have been reported in the medical literature. |
genetic changes | What are the genetic changes related to Baraitser-Winter syndrome ? | Baraitser-Winter syndrome can result from mutations in either the ACTB or ACTG1 gene. These genes provide instructions for making proteins called beta ()-actin and gamma ()-actin, respectively. These proteins are active (expressed) in cells throughout the body. They are organized into a network of fibers called the actin cytoskeleton, which makes up the cell's structural framework. The actin cytoskeleton has several critical functions, including determining cell shape and allowing cells to move. Mutations in the ACTB or ACTG1 gene alter the function of -actin or -actin. The malfunctioning actin causes changes in the actin cytoskeleton that modify the structure and organization of cells and affect their ability to move. Because these two actin proteins are present in cells throughout the body and are involved in many cell activities, problems with their function likely impact many aspects of development, including neuronal migration. These changes underlie the variety of signs and symptoms associated with Baraitser-Winter syndrome. |
inheritance | Is Baraitser-Winter syndrome inherited ? | This condition is described as autosomal dominant, which means one copy of the altered gene in each cell is sufficient to cause the disorder. The condition almost always results from new (de novo) mutations in the ACTB or ACTG1 gene and occurs in people with no history of the disorder in their family. |
treatment | What are the treatments for Baraitser-Winter syndrome ? | These resources address the diagnosis or management of Baraitser-Winter syndrome: - Gene Review: Gene Review: Baraitser-Winter Cerebrofrontofacial Syndrome - Genetic Testing Registry: Baraitser-Winter Syndrome 2 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) methylmalonic acidemia ? | Methylmalonic acidemia is an inherited disorder in which the body is unable to process certain proteins and fats (lipids) properly. The effects of methylmalonic acidemia, which usually appear in early infancy, vary from mild to life-threatening. Affected infants can experience vomiting, dehydration, weak muscle tone (hypotonia), developmental delay, excessive tiredness (lethargy), an enlarged liver (hepatomegaly), and failure to gain weight and grow at the expected rate (failure to thrive). Long-term complications can include feeding problems, intellectual disability, chronic kidney disease, and inflammation of the pancreas (pancreatitis). Without treatment, this disorder can lead to coma and death in some cases. |
frequency | How many people are affected by methylmalonic acidemia ? | This condition occurs in an estimated 1 in 50,000 to 100,000 people. |
genetic changes | What are the genetic changes related to methylmalonic acidemia ? | Mutations in the MUT, MMAA, MMAB, MMADHC, and MCEE genes cause methylmalonic acidemia. The long term effects of methylmalonic acidemia depend on which gene is mutated and the severity of the mutation. About 60 percent of methylmalonic acidemia cases are caused by mutations in the MUT gene. This gene provides instructions for making an enzyme called methylmalonyl CoA mutase. This enzyme works with vitamin B12 (also called cobalamin) to break down several protein building blocks (amino acids), certain lipids, and cholesterol. Mutations in the MUT gene alter the enzyme's structure or reduce the amount of the enzyme, which prevents these molecules from being broken down properly. As a result, a substance called methylmalonyl CoA and other potentially toxic compounds can accumulate in the body's organs and tissues, causing the signs and symptoms of methylmalonic acidemia. Mutations in the MUT gene that prevent the production of any functional enzyme result in a form of the condition designated mut0. Mut0 is the most severe form of methylmalonic acidemia and has the poorest outcome. Mutations that change the structure of methylmalonyl CoA mutase but do not eliminate its activity cause a form of the condition designated mut-. The mut- form is typically less severe, with more variable symptoms than the mut0 form. Some cases of methylmalonic acidemia are caused by mutations in the MMAA, MMAB, or MMADHC gene. Proteins produced from the MMAA, MMAB, and MMADHC genes are needed for the proper function of methylmalonyl CoA mutase. Mutations that affect proteins produced from these three genes can impair the activity of methylmalonyl CoA mutase, leading to methylmalonic acidemia. A few other cases of methylmalonic acidemia are caused by mutations in the MCEE gene. This gene provides instructions for producing an enzyme called methylmalonyl CoA epimerase. Like methylmalonyl CoA mutase, this enzyme also plays a role in the breakdown of amino acids, certain lipids, and cholesterol. Disruption in the function of methylmalonyl CoA epimerase leads to a mild form of methylmalonic acidemia. It is likely that mutations in other, unidentified genes also cause methylmalonic acidemia. |
inheritance | Is methylmalonic acidemia inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the MUT, MMAA, MMAB, MMADHC, or MCEE gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition are carriers of one copy of the mutated gene but do not show signs and symptoms of the condition. |
treatment | What are the treatments for methylmalonic acidemia ? | These resources address the diagnosis or management of methylmalonic acidemia: - Baby's First Test: Methylmalonic Acidemia (Cobalamin Disorders) - Baby's First Test: Methylmalonic Acidemia (Methymalonyl-CoA Mutase Deficiency) - Gene Review: Gene Review: Isolated Methylmalonic Acidemia - Genetic Testing Registry: Methylmalonic acidemia - Genetic Testing Registry: Methylmalonic acidemia with homocystinuria cblD - Genetic Testing Registry: Methylmalonic aciduria cblA type - Genetic Testing Registry: Methylmalonic aciduria cblB type - Genetic Testing Registry: Methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency - Genetic Testing Registry: Methylmalonyl-CoA epimerase deficiency - MedlinePlus Encyclopedia: Methylmalonic acid - MedlinePlus Encyclopedia: Methylmalonic acidemia - New England Consortium of Metabolic Programs These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) congenital hepatic fibrosis ? | Congenital hepatic fibrosis is a disease of the liver that is present from birth. The liver has many important functions, including producing various molecules needed by the body and breaking down other molecules so that their components can be used or eliminated. Congenital hepatic fibrosis is characterized by malformation of the bile ducts and of the blood vessels of the hepatic portal system. Bile ducts carry bile (a fluid that helps to digest fats) from the liver to the gallbladder and small intestine. The hepatic portal system is a branching network of veins (portal veins) that carry blood from the gastrointestinal tract to the liver for processing. A buildup of scar tissue (fibrosis) in the portal tracts also occurs in this disorder. Portal tracts are structures in the liver that bundle the vessels through which blood, lymph, and bile flow, and fibrosis in the portal tracts can restrict the normal movement of fluids in these vessels. Lymph is a fluid that helps exchange immune cells, proteins, and other substances between the blood and tissues. Constriction of the portal veins due to malformation and portal tract fibrosis results in high blood pressure in the hepatic portal system (portal hypertension). Portal hypertension impairs the flow of blood from the gastrointestinal tract, causing an increase in pressure in the veins of the esophagus, stomach, and intestines. These veins may stretch and their walls may become thin, leading to a risk of abnormal bleeding. People with congenital hepatic fibrosis have an enlarged liver and spleen (hepatosplenomegaly). The liver is abnormally shaped. Affected individuals also have an increased risk of infection of the bile ducts (cholangitis), hard deposits in the gallbladder or bile ducts (gallstones), and cancer of the liver or gallbladder. Congenital hepatic fibrosis may occur alone, in which case it is called isolated congenital hepatic fibrosis. More frequently, it occurs as a feature of genetic syndromes that also affect the kidneys (the renal system), such as polycystic kidney disease (PKD). |
frequency | How many people are affected by congenital hepatic fibrosis ? | Isolated congenital hepatic fibrosis is rare. Its prevalence is unknown. The total prevalence of syndromes that include congenital hepatic fibrosis as a feature is estimated to be 1 in 10,000 to 20,000 individuals. |
genetic changes | What are the genetic changes related to congenital hepatic fibrosis ? | Syndromes of which congenital hepatic fibrosis is a feature may be caused by changes in many different genes. The gene changes that cause isolated congenital hepatic fibrosis are unknown. Congenital hepatic fibrosis is caused by problems in the development of the portal veins and bile ducts. These problems include malformation of embryonic structures called ductal plates. Each ductal plate is a cylinder of cells surrounding branches of the portal veins. During development before birth, the ductal plates normally develop into the network of bile ducts. In congenital hepatic fibrosis, the development of the ductal plates does not proceed normally, resulting in the persistence of immature bile ducts. Branching of the portal vein network also proceeds abnormally, and excess fibrous tissue develops in the portal tracts. The malformation of the portal veins and bile ducts disrupts the normal flow of blood and bile, which leads to the progressive signs and symptoms of congenital hepatic fibrosis. |
inheritance | Is congenital hepatic fibrosis inherited ? | The various syndromes of which congenital hepatic fibrosis is often a feature can have different inheritance patterns. Most of these disorders are inherited in an autosomal recessive pattern, which means both copies of the associated 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. Rare syndromes involving congenital hepatic fibrosis may be inherited in an X-linked recessive pattern, in which the gene associated with the syndrome is located on the X chromosome, which is one of the two sex chromosomes. In isolated congenital hepatic fibrosis, the inheritance pattern is unknown. |
treatment | What are the treatments for congenital hepatic fibrosis ? | These resources address the diagnosis or management of congenital hepatic fibrosis: - Gene Review: Gene Review: Congenital Hepatic Fibrosis Overview - Genetic Testing Registry: Congenital hepatic fibrosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) 22q11.2 deletion syndrome ? | 22q11.2 deletion syndrome (which is also known by several other names, listed below) is a disorder caused by the deletion of a small piece of chromosome 22. The deletion occurs near the middle of the chromosome at a location designated q11.2. 22q11.2 deletion syndrome has many possible signs and symptoms that can affect almost any part of the body. The features of this syndrome vary widely, even among affected members of the same family. Common signs and symptoms include heart abnormalities that are often present from birth, an opening in the roof of the mouth (a cleft palate), and distinctive facial features. People with 22q11.2 deletion syndrome often experience recurrent infections caused by problems with the immune system, and some develop autoimmune disorders such as rheumatoid arthritis and Graves disease in which the immune system attacks the body's own tissues and organs. Affected individuals may also have breathing problems, kidney abnormalities, low levels of calcium in the blood (which can result in seizures), a decrease in blood platelets (thrombocytopenia), significant feeding difficulties, gastrointestinal problems, and hearing loss. Skeletal differences are possible, including mild short stature and, less frequently, abnormalities of the spinal bones. Many children with 22q11.2 deletion syndrome have developmental delays, including delayed growth and speech development, and learning disabilities. Later in life, they are at an increased risk of developing mental illnesses such as schizophrenia, depression, anxiety, and bipolar disorder. Additionally, affected children are more likely than children without 22q11.2 deletion syndrome to have attention deficit hyperactivity disorder (ADHD) and developmental conditions such as autism spectrum disorders that affect communication and social interaction. Because the signs and symptoms of 22q11.2 deletion syndrome are so varied, different groupings of features were once described as separate conditions. Doctors named these conditions DiGeorge syndrome, velocardiofacial syndrome (also called Shprintzen syndrome), and conotruncal anomaly face syndrome. In addition, some children with the 22q11.2 deletion were diagnosed with the autosomal dominant form of Opitz G/BBB syndrome and Cayler cardiofacial syndrome. Once the genetic basis for these disorders was identified, doctors determined that they were all part of a single syndrome with many possible signs and symptoms. To avoid confusion, this condition is usually called 22q11.2 deletion syndrome, a description based on its underlying genetic cause. |
frequency | How many people are affected by 22q11.2 deletion syndrome ? | 22q11.2 deletion syndrome affects an estimated 1 in 4,000 people. However, the condition may actually be more common than this estimate because doctors and researchers suspect it is underdiagnosed due to its variable features. The condition may not be identified in people with mild signs and symptoms, or it may be mistaken for other disorders with overlapping features. |
genetic changes | What are the genetic changes related to 22q11.2 deletion syndrome ? | Most people with 22q11.2 deletion syndrome are missing a sequence of about 3 million DNA building blocks (base pairs) on one copy of chromosome 22 in each cell. This region contains 30 to 40 genes, many of which have not been well characterized. A small percentage of affected individuals have shorter deletions in the same region. This condition is described as a contiguous gene deletion syndrome because it results from the loss of many genes that are close together. Researchers are working to identify all of the genes that contribute to the features of 22q11.2 deletion syndrome. They have determined that the loss of a particular gene on chromosome 22, TBX1, is probably responsible for many of the syndrome's characteristic signs (such as heart defects, a cleft palate, distinctive facial features, hearing loss, and low calcium levels). Some studies suggest that a deletion of this gene may contribute to behavioral problems as well. The loss of another gene, COMT, in the same region of chromosome 22 may also help explain the increased risk of behavioral problems and mental illness. The loss of additional genes in the deleted region likely contributes to the varied features of 22q11.2 deletion syndrome. |
inheritance | Is 22q11.2 deletion syndrome inherited ? | The inheritance of 22q11.2 deletion syndrome is considered autosomal dominant because a deletion in one copy of chromosome 22 in each cell is sufficient to cause the condition. Most cases of 22q11.2 deletion syndrome are not inherited, however. The deletion occurs most often as a random event during the formation of reproductive cells (eggs or sperm) or in early fetal development. Affected people typically have no history of the disorder in their family, though they can pass the condition to their children. In about 10 percent of cases, a person with this condition inherits the deletion in chromosome 22 from a parent. In inherited cases, other family members may be affected as well. |
treatment | What are the treatments for 22q11.2 deletion syndrome ? | These resources address the diagnosis or management of 22q11.2 deletion syndrome: - Gene Review: Gene Review: 22q11.2 Deletion Syndrome - Genetic Testing Registry: Asymmetric crying face association - Genetic Testing Registry: DiGeorge sequence - Genetic Testing Registry: Opitz G/BBB syndrome - Genetic Testing Registry: Shprintzen syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) peroxisomal acyl-CoA oxidase deficiency ? | Peroxisomal acyl-CoA oxidase deficiency is a disorder that causes deterioration of nervous system functions (neurodegeneration) beginning in infancy. Newborns with peroxisomal acyl-CoA oxidase deficiency have weak muscle tone (hypotonia) and seizures. They may have unusual facial features, including widely spaced eyes (hypertelorism), a low nasal bridge, and low-set ears. Extra fingers or toes (polydactyly) or an enlarged liver (hepatomegaly) also occur in some affected individuals. Most babies with peroxisomal acyl-CoA oxidase deficiency learn to walk and begin speaking, but they experience a gradual loss of these skills (developmental regression), usually beginning between the ages of 1 and 3. As the condition gets worse, affected children develop exaggerated reflexes (hyperreflexia), increased muscle tone (hypertonia), more severe and recurrent seizures (epilepsy), and loss of vision and hearing. Most children with peroxisomal acyl-CoA oxidase deficiency do not survive past early childhood. |
frequency | How many people are affected by peroxisomal acyl-CoA oxidase deficiency ? | Peroxisomal acyl-CoA oxidase deficiency is a rare disorder. Its prevalence is unknown. Only a few dozen cases have been described in the medical literature. |
genetic changes | What are the genetic changes related to peroxisomal acyl-CoA oxidase deficiency ? | Peroxisomal acyl-CoA oxidase deficiency is caused by mutations in the ACOX1 gene, which provides instructions for making an enzyme called peroxisomal straight-chain acyl-CoA oxidase. This enzyme is found in sac-like cell structures (organelles) called peroxisomes, which contain a variety of enzymes that break down many different substances. The peroxisomal straight-chain acyl-CoA oxidase enzyme plays a role in the breakdown of certain fat molecules called very long-chain fatty acids (VLCFAs). Specifically, it is involved in the first step of a process called the peroxisomal fatty acid beta-oxidation pathway. This process shortens the VLCFA molecules by two carbon atoms at a time until the VLCFAs are converted to a molecule called acetyl-CoA, which is transported out of the peroxisomes for reuse by the cell. ACOX1 gene mutations prevent the peroxisomal straight-chain acyl-CoA oxidase enzyme from breaking down VLCFAs efficiently. As a result, these fatty acids accumulate in the body. It is unclear exactly how VLCFA accumulation leads to the specific features of peroxisomal acyl-CoA oxidase deficiency. However, researchers suggest that the abnormal fatty acid accumulation triggers inflammation in the nervous system that leads to the breakdown of myelin, which is the covering that protects nerves and promotes the efficient transmission of nerve impulses. Destruction of myelin leads to a loss of myelin-containing tissue (white matter) in the brain and spinal cord; loss of white matter is described as leukodystrophy. Leukodystrophy is likely involved in the development of the neurological abnormalities that occur in peroxisomal acyl-CoA oxidase deficiency. |
inheritance | Is peroxisomal acyl-CoA oxidase deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for peroxisomal acyl-CoA oxidase deficiency ? | These resources address the diagnosis or management of peroxisomal acyl-CoA oxidase deficiency: - Gene Review: Gene Review: Leukodystrophy Overview - Genetic Testing Registry: Pseudoneonatal adrenoleukodystrophy These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) 3-M syndrome ? | 3-M syndrome is a disorder that causes short stature (dwarfism), unusual facial features, and skeletal abnormalities. The name of this condition comes from the initials of three researchers who first identified it: Miller, McKusick, and Malvaux. Individuals with 3-M syndrome grow extremely slowly before birth, and this slow growth continues throughout childhood and adolescence. They have low birth weight and length and remain much smaller than others in their family, growing to an adult height of approximately 120 centimeters to 130 centimeters (4 feet to 4 feet 6 inches). Affected individuals have a normally sized head that looks disproportionately large in comparison with their body. The head may be unusually long and narrow in shape (dolichocephalic). In addition to short stature, people with 3-M syndrome have a triangle-shaped face with a broad, prominent forehead (frontal bossing) and a pointed chin; the middle of the face is less prominent (hypoplastic midface). They may have large ears, full eyebrows, an upturned nose with a fleshy tip, a long area between the nose and mouth (philtrum), a prominent mouth, and full lips. Affected individuals may have a short, broad neck and chest with prominent shoulder blades and square shoulders. They may have abnormal spinal curvature such as a rounded upper back that also curves to the side (kyphoscoliosis) or exaggerated curvature of the lower back (hyperlordosis). People with 3-M syndrome may also have unusual curving of the fingers (clinodactyly), short fifth (pinky) fingers, prominent heels, and loose joints. Other skeletal abnormalities, such as unusually slender long bones in the arms and legs, tall, narrow spinal bones (vertebrae), or slightly delayed bone age may be apparent in x-ray images. 3-M syndrome can also affect other body systems. Males with 3-M syndrome may produce reduced amounts of sex hormones (hypogonadism) and occasionally have the urethra opening on the underside of the penis (hypospadias). People with this condition may be at increased risk of developing bulges in blood vessel walls (aneurysms) in the brain. Intelligence is unaffected by 3-M syndrome, and life expectancy is generally normal. A variant of 3-M syndrome called Yakut short stature syndrome has been identified in an isolated population in Siberia. In addition to having most of the physical features characteristic of 3-M syndrome, people with this form of the disorder are often born with respiratory problems that can be life-threatening in infancy. |
frequency | How many people are affected by 3-M syndrome ? | 3-M syndrome is a rare disorder. About 50 individuals with this disorder have been identified worldwide. |
genetic changes | What are the genetic changes related to 3-M syndrome ? | Mutations in the CUL7 gene cause 3-M syndrome. The CUL7 gene provides instructions for making a protein called cullin-7. This protein plays a role in the cell machinery that breaks down (degrades) unwanted proteins, called the ubiquitin-proteasome system. Cullin-7 helps to assemble a complex known as an E3 ubiquitin ligase. This complex tags damaged and excess proteins with molecules called ubiquitin. Ubiquitin serves as a signal to specialized cell structures known as proteasomes, which attach (bind) to the tagged proteins and degrade them. The ubiquitin-proteasome system acts as the cell's quality control system by disposing of damaged, misshapen, and excess proteins. This system also regulates the level of proteins involved in several critical cell activities such as the timing of cell division and growth. Mutations in the CUL7 gene that cause 3-M syndrome disrupt the ability of the cullin-7 protein to bring together the components of the E3 ubiquitin ligase complex, interfering with the process of tagging other proteins with ubiquitin (ubiquitination). It is not known how impaired ubiquitination results in the specific signs and symptoms of 3-M syndrome. |
inheritance | Is 3-M syndrome inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for 3-M syndrome ? | These resources address the diagnosis or management of 3-M syndrome: - Gene Review: Gene Review: 3-M Syndrome - Genetic Testing Registry: Three M syndrome 1 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) 9q22.3 microdeletion ? | 9q22.3 microdeletion is a chromosomal change in which a small piece of chromosome 9 is deleted in each cell. The deletion occurs on the long (q) arm of the chromosome in a region designated q22.3. This chromosomal change is associated with delayed development, intellectual disability, certain physical abnormalities, and the characteristic features of a genetic condition called Gorlin syndrome. Many individuals with a 9q22.3 microdeletion have delayed development, particularly affecting the development of motor skills such as sitting, standing, and walking. In some people, the delays are temporary and improve in childhood. More severely affected individuals have permanent developmental disabilities along with intellectual impairment and learning problems. Rarely, seizures have been reported in people with a 9q22.3 microdeletion. About 20 percent of people with a 9q22.3 microdeletion experience overgrowth (macrosomia), which results in increased height and weight compared to unaffected peers. The macrosomia often begins before birth and continues into childhood. Other physical changes that can be associated with a 9q22.3 microdeletion include the premature fusion of certain bones in the skull (metopic craniosynostosis) and a buildup of fluid in the brain (hydrocephalus). Affected individuals can also have distinctive facial features such as a prominent forehead with vertical skin creases, upward- or downward-slanting eyes, a short nose, and a long space between the nose and upper lip (philtrum). 9q22.3 microdeletions also cause the characteristic features of Gorlin syndrome (also known as nevoid basal cell carcinoma syndrome). This genetic condition affects many areas of the body and increases the risk of developing various cancerous and noncancerous tumors. In people with Gorlin syndrome, the type of cancer diagnosed most often is basal cell carcinoma, which is the most common form of skin cancer. Most people with this condition also develop noncancerous (benign) tumors of the jaw, called keratocystic odontogenic tumors, which can cause facial swelling and tooth displacement. Other types of tumors that occur more often in people with Gorlin syndrome include a form of childhood brain cancer called a medulloblastoma and a type of benign tumor called a fibroma that occurs in the heart or in a woman's ovaries. Other features of Gorlin syndrome include small depressions (pits) in the skin of the palms of the hands and soles of the feet; an unusually large head size (macrocephaly) with a prominent forehead; and skeletal abnormalities involving the spine, ribs, or skull. |
frequency | How many people are affected by 9q22.3 microdeletion ? | 9q22.3 microdeletion appears to be a rare chromosomal change. About three dozen affected individuals have been reported in the medical literature. |
genetic changes | What are the genetic changes related to 9q22.3 microdeletion ? | People with a 9q22.3 microdeletion are missing a sequence of at least 352,000 DNA building blocks (base pairs), also written as 352 kilobases (kb), in the q22.3 region of chromosome 9. This 352-kb segment is known as the minimum critical region because it is the smallest deletion that has been found to cause the signs and symptoms described above. 9q22.3 microdeletions can also be much larger; the largest reported deletion includes 20.5 million base pairs (20.5 Mb). 9q22.3 microdeletion affects one of the two copies of chromosome 9 in each cell. People with a 9q22.3 microdeletion are missing from two to more than 270 genes on chromosome 9. All known 9q22.3 microdeletions include the PTCH1 gene. The protein produced from this gene, patched-1, acts as a tumor suppressor, which means it keeps cells from growing and dividing (proliferating) too rapidly or in an uncontrolled way. Researchers believe that many of the features associated with 9q22.3 microdeletions, particularly the signs and symptoms of Gorlin syndrome, result from a loss of the PTCH1 gene. When this gene is missing, patched-1 is not available to suppress cell proliferation. As a result, cells divide uncontrollably to form the tumors that are characteristic of Gorlin syndrome. Other signs and symptoms related to 9q22.3 microdeletions probably result from the loss of additional genes in the q22.3 region. Researchers are working to determine which missing genes contribute to the other features associated with the deletion. |
inheritance | Is 9q22.3 microdeletion inherited ? | 9q22.3 microdeletions are inherited in an autosomal dominant pattern, which means that missing genetic material from one of the two copies of chromosome 9 in each cell is sufficient to cause delayed development, intellectual disability, and the features of Gorlin syndrome. A 9q22.3 microdeletion most often occurs in people whose parents do not carry the chromosomal change. In these cases, the deletion occurs as a random (de novo) event during the formation of reproductive cells (eggs or sperm) in a parent or in early embryonic development. De novo chromosomal changes occur in people with no history of the disorder in their family. Less commonly, individuals with a 9q22.3 microdeletion inherit the chromosomal change from an unaffected parent. In these cases, the parent carries a chromosomal rearrangement called a balanced translocation, in which a segment of chromosome 9 has traded places with a segment of another chromosome. 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. People who inherit a 9q22.3 microdeletion receive an unbalanced translocation that deletes genetic material from one copy of the q22.3 region of chromosome 9 in each cell. Having one missing copy of the PTCH1 gene in each cell is enough to cause the features of Gorlin syndrome that are present early in life, including macrocephaly and skeletal abnormalities. For basal cell carcinomas and other tumors to develop, a mutation in the other copy of the PTCH1 gene must also occur in certain cells during the person's lifetime. Most people who are born with one missing copy of the PTCH1 gene eventually acquire a mutation in the other copy of the gene in some cells and consequently develop various types of tumors. |
treatment | What are the treatments for 9q22.3 microdeletion ? | These resources address the diagnosis or management of 9q22.3 microdeletion: - Gene Review: Gene Review: 9q22.3 Microdeletion - Gene Review: Gene Review: Nevoid Basal Cell Carcinoma Syndrome - Genetic Testing Registry: Gorlin syndrome - MedlinePlus Encyclopedia: Basal Cell Nevus Syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) collagen VI-related myopathy ? | Collagen VI-related myopathy is a group of disorders that affect skeletal muscles (which are the muscles used for movement) and connective tissue (which provides strength and flexibility to the skin, joints, and other structures throughout the body). Most affected individuals have muscle weakness and joint deformities called contractures that restrict movement of the affected joints and worsen over time. Researchers have described several forms of collagen VI-related myopathy, which range in severity: Bethlem myopathy is the mildest, an intermediate form is moderate in severity, and Ullrich congenital muscular dystrophy is the most severe. People with Bethlem myopathy usually have loose joints (joint laxity) and weak muscle tone (hypotonia) in infancy, but they develop contractures during childhood, typically in their fingers, wrists, elbows, and ankles. Muscle weakness can begin at any age but often appears in childhood to early adulthood. The muscle weakness is slowly progressive, with about two-thirds of affected individuals over age 50 needing walking assistance. Older individuals may develop weakness in respiratory muscles, which can cause breathing problems. Some people with this mild form of collagen VI-related myopathy have skin abnormalities, including small bumps called follicular hyperkeratosis on the arms and legs; soft, velvety skin on the palms of the hands and soles of the feet; and abnormal wound healing that creates shallow scars. The intermediate form of collagen VI-related myopathy is characterized by muscle weakness that begins in infancy. Affected children are able to walk, although walking becomes increasingly difficult starting in early adulthood. They develop contractures in the ankles, elbows, knees, and spine in childhood. In some affected people, the respiratory muscles are weakened, requiring people to use a machine to help them breathe (mechanical ventilation), particularly during sleep. People with Ullrich congenital muscular dystrophy have severe muscle weakness beginning soon after birth. Some affected individuals are never able to walk and others can walk only with support. Those who can walk often lose the ability, usually in adolescence. Individuals with Ullrich congenital muscular dystrophy develop contractures in their neck, hips, and knees, which further impair movement. There may be joint laxity in the fingers, wrists, toes, ankles, and other joints. Some affected individuals need continuous mechanical ventilation to help them breathe. As in Bethlem myopathy, some people with Ullrich congenital muscular dystrophy have follicular hyperkeratosis; soft, velvety skin on the palms and soles; and abnormal wound healing. Individuals with collagen VI-related myopathy often have signs and symptoms of multiple forms of this condition, so it can be difficult to assign a specific diagnosis. The overlap in disease features, in addition to their common cause, is why these once separate conditions are now considered part of the same disease spectrum. |
frequency | How many people are affected by collagen VI-related myopathy ? | Collagen VI-related myopathy is rare. Bethlem myopathy is estimated to occur in 0.77 per 100,000 individuals, and Ullrich congenital muscular dystrophy is estimated to occur in 0.13 per 100,000 individuals. Only a few cases of the intermediate form have been described in the scientific literature. |
genetic changes | What are the genetic changes related to collagen VI-related myopathy ? | Mutations in the COL6A1, COL6A2, and COL6A3 genes can cause the various forms of collagen VI-related myopathy. These genes each provide instructions for making one component of a protein called type VI collagen. Type VI collagen makes up part of the extracellular matrix that surrounds muscle cells and connective tissue. This matrix is an intricate lattice that forms in the space between cells and provides structural support. The extracellular matrix is necessary for cell stability and growth. Research suggests that type VI collagen helps secure and organize the extracellular matrix by linking the matrix to the cells it surrounds. Mutations in the COL6A1, COL6A2, and COL6A3 genes result in a decrease or lack of type VI collagen or the production of abnormal type VI collagen. While it is difficult to predict which type of mutation will lead to which form of collagen VI-related myopathy, in general, lower amounts of type VI collagen lead to more severe signs and symptoms that begin earlier in life. Changes in type VI collagen structure or production lead to an unstable extracellular matrix that is no longer attached to cells. As a result, the stability of the surrounding muscle cells and connective tissue progressively declines, which leads to the muscle weakness, contractures, and other signs and symptoms of collagen VI-related myopathy. |
inheritance | Is collagen VI-related myopathy inherited ? | Collagen VI-related myopathy can be inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Bethlem myopathy is typically inherited in an autosomal dominant manner, as are some cases of the intermediate form and a few rare instances of Ullrich congenital muscular dystrophy. Most cases result from new mutations in the gene and occur in people with no history of the disorder in their family. In other cases, an affected person inherits the mutation from one affected parent. Collagen VI-related myopathy can be inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Ullrich congenital muscular dystrophy is typically inherited in an autosomal recessive manner, as are some cases of the intermediate form and a few rare instances of Bethlem myopathy. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for collagen VI-related myopathy ? | These resources address the diagnosis or management of collagen VI-related myopathy: - Gene Review: Gene Review: Collagen Type VI-Related Disorders - Genetic Testing Registry: Bethlem myopathy - Genetic Testing Registry: Collagen Type VI-Related Autosomal Dominant Limb-girdle Muscular Dystrophy - Genetic Testing Registry: Collagen VI-related myopathy - Genetic Testing Registry: Ullrich congenital muscular dystrophy - Muscular Dystrophy UK: Could Cyclosporine A be used to treat Bethlem myopathy and Ullrich congenital muscular dystrophy? These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) hereditary neuropathy with liability to pressure palsies ? | Hereditary neuropathy with liability to pressure palsies is a disorder that affects peripheral nerves. These nerves connect the brain and spinal cord to muscles as well as sensory cells that detect touch, pain, and temperature. In people with this disorder, the peripheral nerves are unusually sensitive to pressure. Hereditary neuropathy with liability to pressure palsies causes recurrent episodes of numbness, tingling, and/or loss of muscle function (palsy). An episode can last from several minutes to several months, but recovery is usually complete. Repeated incidents, however, can cause permanent muscle weakness or loss of sensation. This disorder is also associated with pain in the limbs, especially the hands. A pressure palsy episode results from problems in a single nerve, but any peripheral nerve can be affected. Episodes often recur, but not always at the same site. The most common problem sites involve nerves in wrists, elbows, and knees. Fingers, shoulders, hands, feet, and the scalp can also be affected. Many people with this disorder experience carpal tunnel syndrome when a nerve in the wrist (the median nerve) is involved. Carpal tunnel syndrome is characterized by numbness, tingling, and weakness in the hand and fingers. An episode in the hand may affect fine motor activities such as writing, opening jars, and fastening buttons. An episode in the leg can make walking, climbing stairs, or driving difficult or impossible. Symptoms usually begin during adolescence or early adulthood but may develop anytime from childhood to late adulthood. Symptoms vary in severity; many people never realize they have the disorder, while some people experience prolonged disability. Hereditary neuropathy with liability to pressure palsies does not affect life expectancy. |
frequency | How many people are affected by hereditary neuropathy with liability to pressure palsies ? | Hereditary neuropathy with liability to pressure palsies is estimated to occur in 2 to 5 per 100,000 individuals. |
genetic changes | What are the genetic changes related to hereditary neuropathy with liability to pressure palsies ? | Mutations in the PMP22 gene cause hereditary neuropathy with liability to pressure palsies. Hereditary neuropathy with liability to pressure palsies is caused by the loss of one copy of the PMP22 gene or alterations within the gene. The consequences of PMP22 gene mutations are not clearly understood. Most likely, PMP22 gene mutations affect myelin, the protective substance that covers nerve cells. As a result of these mutations, some of the protective myelin covering may become unstable, which leads to increased sensitivity to pressure on the nerves. |
inheritance | Is hereditary neuropathy with liability to pressure palsies inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. |
treatment | What are the treatments for hereditary neuropathy with liability to pressure palsies ? | These resources address the diagnosis or management of hereditary neuropathy with liability to pressure palsies: - Gene Review: Gene Review: Hereditary Neuropathy with Liability to Pressure Palsies - Genetic Testing Registry: Hereditary liability to pressure palsies - MedlinePlus Encyclopedia: carpal tunnel syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) 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. |
frequency | 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. |
genetic changes | 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. |
inheritance | 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. |
treatment | 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 |
information | What is (are) atelosteogenesis type 3 ? | Atelosteogenesis type 3 is a disorder that affects the development of bones throughout the body. Affected individuals are born with inward- and upward-turning feet (clubfeet) and dislocations of the hips, knees, and elbows. Bones in the spine, rib cage, pelvis, and limbs may be underdeveloped or in some cases absent. As a result of the limb bone abnormalities, individuals with this condition have very short arms and legs. Their hands and feet are wide, with broad fingers and toes that may be permanently bent (camptodactyly) or fused together (syndactyly). Characteristic facial features include a broad forehead, wide-set eyes (hypertelorism), and an underdeveloped nose. About half of affected individuals have an opening in the roof of the mouth (a cleft palate.) Individuals with atelosteogenesis type 3 typically have an underdeveloped rib cage that affects the development and functioning of the lungs. As a result, affected individuals are usually stillborn or die shortly after birth from respiratory failure. Some affected individuals survive longer, usually with intensive medical support. They typically experience further respiratory problems as a result of weakness of the airways that can lead to partial closing, short pauses in breathing (apnea), or frequent infections. People with atelosteogenesis type 3 who survive past the newborn period may have learning disabilities and delayed language skills, which are probably caused by low levels of oxygen in the brain due to respiratory problems. As a result of their orthopedic abnormalities, they also have delayed development of motor skills such as standing and walking. |
frequency | How many people are affected by atelosteogenesis type 3 ? | Atelosteogenesis type 3 is a rare disorder; its exact prevalence is unknown. About two dozen affected individuals have been identified. |
genetic changes | What are the genetic changes related to atelosteogenesis type 3 ? | Mutations in the FLNB gene cause atelosteogenesis type 3. The FLNB gene provides instructions for making a protein called filamin B. This protein helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Filamin B attaches (binds) to another protein called actin and helps the actin to form the branching network of filaments that makes up the cytoskeleton. It also links actin to many other proteins to perform various functions within the cell, including the cell signaling that helps determine how the cytoskeleton will change as tissues grow and take shape during development. Filamin B is especially important in the development of the skeleton before birth. It is active (expressed) in the cell membranes of cartilage-forming cells (chondrocytes). Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone (a process called ossification), except for the cartilage that continues to cover and protect the ends of bones and is present in the nose, airways (trachea and bronchi), and external ears. Filamin B appears to be important for normal cell growth and division (proliferation) and maturation (differentiation) of chondrocytes and for the ossification of cartilage. FLNB gene mutations that cause atelosteogenesis type 3 change single protein building blocks (amino acids) in the filamin B protein or delete a small section of the protein sequence, resulting in an abnormal protein. This abnormal protein appears to have a new, atypical function that interferes with the proliferation or differentiation of chondrocytes, impairing ossification and leading to the signs and symptoms of atelosteogenesis type 3. |
inheritance | Is atelosteogenesis type 3 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. Most cases result from new mutations in the gene and occur in people with no history of the disorder in their family. |
treatment | What are the treatments for atelosteogenesis type 3 ? | These resources address the diagnosis or management of atelosteogenesis type 3: - Gene Review: Gene Review: FLNB-Related Disorders - Genetic Testing Registry: Atelosteogenesis type 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 |
information | What is (are) Walker-Warburg syndrome ? | Walker-Warburg syndrome is an inherited disorder that affects development of the muscles, brain, and eyes. It is the most severe of a group of genetic conditions known as congenital muscular dystrophies, which cause muscle weakness and wasting (atrophy) beginning very early in life. The signs and symptoms of Walker-Warburg syndrome are present at birth or in early infancy. Because of the severity of the problems caused by Walker-Warburg syndrome, most affected individuals do not survive past age 3. Walker-Warburg syndrome affects the skeletal muscles, which are muscles the body uses for movement. Affected babies have weak muscle tone (hypotonia) and are sometimes described as "floppy." The muscle weakness worsens over time. Walker-Warburg syndrome also affects the brain; individuals with this condition typically have a brain abnormality called cobblestone lissencephaly, in which the surface of the brain lacks the normal folds and grooves and instead develops a bumpy, irregular appearance (like that of cobblestones). They may also have a buildup of fluid in the brain (hydrocephalus) or abnormalities of other parts of the brain, including a region called the cerebellum and the part of the brain that connects to the spinal cord (the brainstem). These changes in the structure of the brain lead to significantly delayed development and intellectual disability. Some individuals with Walker-Warburg syndrome experience seizures. Eye abnormalities are also characteristic of Walker-Warburg syndrome. These can include unusually small eyeballs (microphthalmia), enlarged eyeballs caused by increased pressure in the eyes (buphthalmos), clouding of the lenses of the eyes (cataracts), and problems with the nerve that relays visual information from the eyes to the brain (the optic nerve). These eye problems lead to vision impairment in affected individuals. |
frequency | How many people are affected by Walker-Warburg syndrome ? | Walker-Warburg syndrome is estimated to affect 1 in 60,500 newborns worldwide. |
genetic changes | What are the genetic changes related to Walker-Warburg syndrome ? | Walker-Warburg syndrome can be caused by mutations in one of several genes, including POMT1, POMT2, ISPD, FKTN, FKRP, and LARGE. The proteins produced from these genes modify another protein called alpha ()-dystroglycan; this modification, called glycosylation, is required for -dystroglycan to function. The -dystroglycan protein helps anchor the structural framework inside each cell (cytoskeleton) to the lattice of proteins and other molecules outside the cell (extracellular matrix). In skeletal muscles, the anchoring function of -dystroglycan helps stabilize and protect muscle fibers. In the brain, it helps direct the movement (migration) of nerve cells (neurons) during early development. Mutations in these genes prevent glycosylation of -dystroglycan, which disrupts its normal function. Without functional -dystroglycan to stabilize muscle cells, muscle fibers become damaged as they repeatedly contract and relax with use. The damaged fibers weaken and die over time, leading to progressive weakness of the skeletal muscles. Defective -dystroglycan also affects the migration of neurons during the early development of the brain. Instead of stopping when they reach their intended destinations, some neurons migrate past the surface of the brain into the fluid-filled space that surrounds it. Researchers believe that this problem with neuronal migration causes cobblestone lissencephaly in children with Walker-Warburg syndrome. Less is known about the effects of the gene mutations in other parts of the body, including the eyes. Mutations in the POMT1, POMT2, ISPD, FKTN, FKRP, and LARGE genes are found in only about half of individuals with Walker-Warburg syndrome. Other genes, some of which have not been identified, are likely involved in the development of this condition. Because Walker-Warburg syndrome involves a malfunction of -dystroglycan, this condition is classified as a dystroglycanopathy. |
inheritance | Is Walker-Warburg syndrome inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for Walker-Warburg syndrome ? | These resources address the diagnosis or management of Walker-Warburg syndrome: - Gene Review: Gene Review: Congenital Muscular Dystrophy Overview - Genetic Testing Registry: Walker-Warburg congenital muscular dystrophy These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) Smith-Magenis syndrome ? | Smith-Magenis syndrome is a developmental disorder that affects many parts of the body. The major features of this condition include mild to moderate intellectual disability, delayed speech and language skills, distinctive facial features, sleep disturbances, and behavioral problems. Most people with Smith-Magenis syndrome have a broad, square-shaped face with deep-set eyes, full cheeks, and a prominent lower jaw. The middle of the face and the bridge of the nose often appear flattened. The mouth tends to turn downward with a full, outward-curving upper lip. These facial differences can be subtle in early childhood, but they usually become more distinctive in later childhood and adulthood. Dental abnormalities are also common in affected individuals. Disrupted sleep patterns are characteristic of Smith-Magenis syndrome, typically beginning early in life. Affected people may be very sleepy during the day, but they have trouble falling asleep and awaken several times each night. People with Smith-Magenis syndrome have affectionate, engaging personalities, but most also have behavioral problems. These include frequent temper tantrums and outbursts, aggression, anxiety, impulsiveness, and difficulty paying attention. Self-injury, including biting, hitting, head banging, and skin picking, is very common. Repetitive self-hugging is a behavioral trait that may be unique to Smith-Magenis syndrome. People with this condition also compulsively lick their fingers and flip pages of books and magazines (a behavior known as "lick and flip"). Other signs and symptoms of Smith-Magenis syndrome include short stature, abnormal curvature of the spine (scoliosis), reduced sensitivity to pain and temperature, and a hoarse voice. Some people with this disorder have ear abnormalities that lead to hearing loss. Affected individuals may have eye abnormalities that cause nearsightedness (myopia) and other vision problems. Although less common, heart and kidney defects also have been reported in people with Smith-Magenis syndrome. |
frequency | How many people are affected by Smith-Magenis syndrome ? | Smith-Magenis syndrome affects at least 1 in 25,000 individuals worldwide. Researchers believe that many people with this condition are not diagnosed, however, so the true prevalence may be closer to 1 in 15,000 individuals. |
genetic changes | What are the genetic changes related to Smith-Magenis syndrome ? | Most people with Smith-Magenis syndrome have a deletion of genetic material from a specific region of chromosome 17. Although this region contains multiple genes, researchers believe that the loss of one particular gene, RAI1, in each cell is responsible for most of the characteristic features of this condition. The loss of other genes in the deleted region may help explain why the features of Smith-Magenis syndrome vary among affected individuals. A small percentage of people with Smith-Magenis syndrome have a mutation in the RAI1 gene instead of a chromosomal deletion. Although these individuals have many of the major features of the condition, they are less likely than people with a chromosomal deletion to have short stature, hearing loss, and heart or kidney abnormalities. The RAI1 gene provides instructions for making a protein whose function is unknown. Mutations in one copy of this gene lead to the production of a nonfunctional version of the RAI1 protein or reduce the amount of this protein that is produced in cells. Researchers are uncertain how changes in this protein result in the physical, mental, and behavioral problems associated with Smith-Magenis syndrome. |
inheritance | Is Smith-Magenis syndrome inherited ? | Smith-Magenis syndrome is typically not inherited. This condition usually results from a genetic change that occurs during the formation of reproductive cells (eggs or sperm) or in early fetal development. Most often, people with Smith-Magenis syndrome have no history of the condition in their family. |
treatment | What are the treatments for Smith-Magenis syndrome ? | These resources address the diagnosis or management of Smith-Magenis syndrome: - Gene Review: Gene Review: Smith-Magenis Syndrome - Genetic Testing Registry: Smith-Magenis syndrome - MedlinePlus Encyclopedia: Intellectual Disability These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) glycogen storage disease type VI ? | Glycogen storage disease type VI (also known as GSDVI or Hers disease) is an inherited disorder caused by an inability to break down a complex sugar called glycogen in liver cells. A lack of glycogen breakdown interferes with the normal function of the liver. The signs and symptoms of GSDVI typically begin in infancy to early childhood. The first sign is usually an enlarged liver (hepatomegaly). Affected individuals may also have low blood sugar (hypoglycemia) or a buildup of lactic acid in the body (lactic acidosis) during prolonged periods without food (fasting). The signs and symptoms of GSDVI tend to improve with age; most adults with this condition do not have any related health problems. |
frequency | How many people are affected by glycogen storage disease type VI ? | The exact prevalence of GSDVI is unknown. At least 11 cases have been reported in the medical literature, although this condition is likely to be underdiagnosed because it can be difficult to detect in children with mild symptoms or adults with no symptoms. GSDVI is more common in the Old Older Mennonite population, with an estimated incidence of 1 in 1,000 individuals. |
genetic changes | What are the genetic changes related to glycogen storage disease type VI ? | Mutations in the PYGL gene cause GSDVI. The PYGL gene provides instructions for making an enzyme called liver glycogen phosphorylase. This enzyme is found only in liver cells, where it breaks down glycogen into a type of sugar called glucose-1-phosphate. Additional steps convert glucose-1-phosphate into glucose, a simple sugar that is the main energy source for most cells in the body. PYGL gene mutations prevent liver glycogen phosphorylase from breaking down glycogen effectively. As a result, liver cells cannot use glycogen for energy. Since glycogen cannot be broken down, it accumulates within liver cells, causing these cells to become enlarged and dysfunctional. |
inheritance | Is glycogen storage disease type VI inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. |
treatment | What are the treatments for glycogen storage disease type VI ? | These resources address the diagnosis or management of glycogen storage disease type VI: - Gene Review: Gene Review: Glycogen Storage Disease Type VI - Genetic Testing Registry: Glycogen storage disease, type VI These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
information | What is (are) ring chromosome 14 syndrome ? | Ring chromosome 14 syndrome is a condition characterized by seizures and intellectual disability. Recurrent seizures (epilepsy) develop in infancy or early childhood. In many cases, the seizures are resistant to treatment with anti-epileptic drugs. Most people with ring chromosome 14 syndrome also have some degree of intellectual disability or learning problems. Development may be delayed, particularly the development of speech and of motor skills such as sitting, standing, and walking. Additional features of ring chromosome 14 syndrome can include slow growth and short stature, a small head (microcephaly), puffy hands and/or feet caused by a buildup of fluid (lymphedema), and subtle differences in facial features. Some affected individuals have problems with their immune system that lead to recurrent infections, especially involving the respiratory system. Abnormalities of the retina, the specialized tissue at the back of the eye that detects light and color, have also been reported in some people with this condition. These changes typically do not affect vision. Major birth defects are rarely seen with ring chromosome 14 syndrome. |
frequency | How many people are affected by ring chromosome 14 syndrome ? | Ring chromosome 14 syndrome appears to be a rare condition, although its prevalence is unknown. More than 50 affected individuals have been reported in the medical literature. |
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