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What is (are) Usher syndrome ? | Usher syndrome is a condition characterized by hearing loss or deafness and progressive vision loss. The loss of vision is caused by an eye disease called retinitis pigmentosa (RP), which affects the layer of light-sensitive tissue at the back of the eye (the retina). Vision loss occurs as the light-sensing cells of the retina gradually deteriorate. Night vision loss begins first, followed by blind spots that develop in the side (peripheral) vision. Over time, these blind spots enlarge and merge to produce tunnel vision. In some cases of Usher syndrome, vision is further impaired by clouding of the lens of the eye (cataracts). Many people with retinitis pigmentosa retain some central vision throughout their lives, however. Researchers have identified three major types of Usher syndrome, designated as types I, II, and III. These types are distinguished by their severity and the age when signs and symptoms appear. Type I is further divided into seven distinct subtypes, designated as types IA through IG. Usher syndrome type II has at least three described subtypes, designated as types IIA, IIB, and IIC. Individuals with Usher syndrome type I are typically born completely deaf or lose most of their hearing within the first year of life. Progressive vision loss caused by retinitis pigmentosa becomes apparent in childhood. This type of Usher syndrome also includes problems with the inner ear that affect balance. As a result, children with the condition begin sitting independently and walking later than usual. Usher syndrome type II is characterized by hearing loss from birth and progressive vision loss that begins in adolescence or adulthood. The hearing loss associated with this form of Usher syndrome ranges from mild to severe and mainly affects high tones. Affected children have problems hearing high, soft speech sounds, such as those of the letters d and t. The degree of hearing loss varies within and among families with this condition. Unlike other forms of Usher syndrome, people with type II do not have difficulties with balance caused by inner ear problems. People with Usher syndrome type III experience progressive hearing loss and vision loss beginning in the first few decades of life. Unlike the other forms of Usher syndrome, infants with Usher syndrome type III are usually born with normal hearing. Hearing loss typically begins during late childhood or adolescence, after the development of speech, and progresses over time. By middle age, most affected individuals are profoundly deaf. Vision loss caused by retinitis pigmentosa also develops in late childhood or adolescence. People with Usher syndrome type III may also experience difficulties with balance due to inner ear problems. These problems vary among affected individuals, however. | Usher syndrome |
How many people are affected by Usher syndrome ? | Usher syndrome is thought to be responsible for 3 percent to 6 percent of all childhood deafness and about 50 percent of deaf-blindness in adults. Usher syndrome type I is estimated to occur in at least 4 per 100,000 people. It may be more common in certain ethnic populations, such as people with Ashkenazi (central and eastern European) Jewish ancestry and the Acadian population in Louisiana. Type II is thought to be the most common form of Usher syndrome, although the frequency of this type is unknown. Type III Usher syndrome accounts for only a small percentage of all Usher syndrome cases in most populations. This form of the condition is more common in the Finnish population, however, where it accounts for about 40 percent of all cases. | Usher syndrome |
What are the genetic changes related to Usher syndrome ? | Mutations in the ADGRV1, CDH23, CLRN1, MYO7A, PCDH15, USH1C, USH1G, and USH2A genes can cause Usher syndrome. The genes related to Usher syndrome provide instructions for making proteins that play important roles in normal hearing, balance, and vision. They function in the development and maintenance of hair cells, which are sensory cells in the inner ear that help transmit sound and motion signals to the brain. In the retina, these genes are also involved in determining the structure and function of light-sensing cells called rods and cones. In some cases, the exact role of these genes in hearing and vision is unknown. Most of the mutations responsible for Usher syndrome lead to a loss of hair cells in the inner ear and a gradual loss of rods and cones in the retina. Degeneration of these sensory cells causes hearing loss, balance problems, and vision loss characteristic of this condition. Usher syndrome type I can result from mutations in the CDH23, MYO7A, PCDH15, USH1C, or USH1G gene. At least two other unidentified genes also cause this form of Usher syndrome. Usher syndrome type II is caused by mutations in at least four genes. Only two of these genes, ADGRV1 and USH2A, have been identified. Mutations in at least two genes are responsible for Usher syndrome type III; however, CLRN1 is the only gene that has been identified. | Usher syndrome |
Is Usher 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. | Usher syndrome |
What are the treatments for Usher syndrome ? | These resources address the diagnosis or management of Usher syndrome: - Gene Review: Gene Review: Usher Syndrome Type I - Gene Review: Gene Review: Usher Syndrome Type II - Genetic Testing Registry: Usher syndrome type 2 - Genetic Testing Registry: Usher syndrome, type 1 - Genetic Testing Registry: Usher syndrome, type 3A - MedlinePlus Encyclopedia: Retinitis Pigmentosa 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 | Usher syndrome |
What is (are) mal de Meleda ? | Mal de Meleda is a rare skin disorder that begins in early infancy. Affected individuals have a condition known as palmoplantar keratoderma, in which the skin of the palms of the hands and soles of the feet becomes thick, hard, and callused. In mal de Meleda, the thickened skin is also found on the back of the hands and feet and on the wrists and ankles. In addition, affected individuals may have rough, thick pads on the joints of the fingers and toes and on the elbows and knees. Some people with mal de Meleda have recurrent fungal infections in the thickened skin, which can lead to a strong odor. Other features of this disorder can include short fingers and toes (brachydactyly), nail abnormalities, red skin around the mouth, and excessive sweating (hyperhidrosis). | mal de Meleda |
How many people are affected by mal de Meleda ? | Mal de Meleda is a rare disorder; its prevalence is unknown. The disorder was first identified on the Croatian island of Mjlet (called Meleda in Italian) and has since been found in populations worldwide. | mal de Meleda |
What are the genetic changes related to mal de Meleda ? | Mal de Meleda is caused by mutations in the SLURP1 gene. This gene provides instructions for making a protein that interacts with other proteins, called receptors, and is likely involved in signaling within cells. Studies show that the SLURP-1 protein can attach (bind) to nicotinic acetylcholine receptors (nAChRs) in the skin. Through interaction with these receptors, the SLURP-1 protein is thought to be involved in controlling the growth and division (proliferation), maturation (differentiation), and survival of skin cells. Mutations in the SLURP1 gene lead to little or no SLURP-1 protein in the body. It is unclear how a lack of this protein leads to the skin problems that occur in mal de Meleda. Researchers speculate that without SLURP-1, the activity of genes controlled by nAChR signaling is altered, leading to overgrowth of skin cells or survival of cells that normally would have died. The excess of cells can result in skin thickening. It is unclear why skin on the hands and feet is particularly affected. | mal de Meleda |
Is mal de Meleda 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. | mal de Meleda |
What are the treatments for mal de Meleda ? | These resources address the diagnosis or management of mal de Meleda: - Foundation for Ichthyosis and Related Skin Types: Palmoplantar Keratodermas - Genetic Testing Registry: Acroerythrokeratoderma 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 | mal de Meleda |
What is (are) Salih myopathy ? | Salih myopathy is an inherited muscle disease that affects the skeletal muscles, which are used for movement, and the heart (cardiac) muscle. This condition is characterized by skeletal muscle weakness that becomes apparent in early infancy. Affected individuals have delayed development of motor skills, such as sitting, standing, and walking. Beginning later in childhood, people with Salih myopathy may also develop joint deformities called contractures that restrict the movement of the neck and back. Scoliosis, which is an abnormal side-to-side curvature of the spine, also develops in late childhood. A form of heart disease called dilated cardiomyopathy is another feature of Salih myopathy. Dilated cardiomyopathy enlarges and weakens the cardiac muscle, preventing the heart from pumping blood efficiently. Signs and symptoms of this condition can include an irregular heartbeat (arrhythmia), shortness of breath, extreme tiredness (fatigue), and swelling of the legs and feet. The heart abnormalities associated with Salih myopathy usually become apparent in childhood, after the skeletal muscle abnormalities. The heart disease worsens quickly, and it often causes heart failure and sudden death in adolescence or early adulthood. | Salih myopathy |
How many people are affected by Salih myopathy ? | Salih myopathy appears to be a rare disorder, although its prevalence is unknown. It has been reported in a small number of families of Moroccan and Sudanese descent. | Salih myopathy |
What are the genetic changes related to Salih myopathy ? | Salih myopathy is caused by mutations in the TTN gene. This gene provides instructions for making a protein called titin, which plays an important role in skeletal and cardiac muscle function. Within muscle cells, titin is an essential component of structures called sarcomeres. Sarcomeres are the basic units of muscle contraction; they are made of proteins that generate the mechanical force needed for muscles to contract. Titin has several functions within sarcomeres. One of this protein's most important jobs is to provide structure, flexibility, and stability to these cell structures. Titin also plays a role in chemical signaling and in assembling new sarcomeres. The TTN gene mutations responsible for Salih myopathy lead to the production of an abnormally short version of titin. The defective protein disrupts the function of sarcomeres, which prevents skeletal and cardiac muscle from contracting normally. These muscle abnormalities underlie the features of Salih myopathy, including skeletal muscle weakness and dilated cardiomyopathy. | Salih myopathy |
Is Salih myopathy 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. | Salih myopathy |
What are the treatments for Salih myopathy ? | These resources address the diagnosis or management of Salih myopathy: - Gene Review: Gene Review: Salih Myopathy - Genetic Testing Registry: Myopathy, early-onset, with fatal cardiomyopathy 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 | Salih myopathy |
What is (are) hereditary antithrombin deficiency ? | Hereditary antithrombin deficiency is a disorder of blood clotting. People with this condition are at higher than average risk for developing abnormal blood clots, particularly a type of clot that occurs in the deep veins of the legs. This type of clot is called a deep vein thrombosis (DVT). Affected individuals also have an increased risk of developing a pulmonary embolism (PE), which is a clot that travels through the bloodstream and lodges in the lungs. In hereditary antithrombin deficiency, abnormal blood clots usually form only in veins, although they may rarely occur in arteries. About half of people with hereditary antithrombin deficiency will develop at least one abnormal blood clot during their lifetime. These clots usually develop after adolescence. Other factors can increase the risk of abnormal blood clots in people with hereditary antithrombin deficiency. These factors include increasing age, surgery, or immobility. The combination of hereditary antithrombin deficiency and other inherited disorders of blood clotting can also influence risk. Women with hereditary antithrombin deficiency are at increased risk of developing an abnormal blood clot during pregnancy or soon after delivery. They also may have an increased risk for pregnancy loss (miscarriage) or stillbirth. | hereditary antithrombin deficiency |
How many people are affected by hereditary antithrombin deficiency ? | Hereditary antithrombin deficiency is estimated to occur in about 1 in 2,000 to 3,000 individuals. Of people who have experienced an abnormal blood clot, about 1 in 20 to 200 have hereditary antithrombin deficiency. | hereditary antithrombin deficiency |
What are the genetic changes related to hereditary antithrombin deficiency ? | Hereditary antithrombin deficiency is caused by mutations in the SERPINC1 gene. This gene provides instructions for producing a protein called antithrombin (previously known as antithrombin III). This protein is found in the bloodstream and is important for controlling blood clotting. Antithrombin blocks the activity of proteins that promote blood clotting, especially a protein called thrombin. Most of the mutations that cause hereditary antithrombin deficiency change single protein building blocks (amino acids) in antithrombin, which disrupts its ability to control blood clotting. Individuals with this condition do not have enough functional antithrombin to inactivate clotting proteins, which results in the increased risk of developing abnormal blood clots. | hereditary antithrombin deficiency |
Is hereditary antithrombin deficiency inherited ? | Hereditary antithrombin deficiency is typically inherited in an autosomal dominant pattern, which means one altered copy of the SERPINC1 gene in each cell is sufficient to cause the disorder. Inheriting two altered copies of this gene in each cell is usually incompatible with life; however, a few severely affected individuals have been reported with mutations in both copies of the SERPINC1 gene in each cell. | hereditary antithrombin deficiency |
What are the treatments for hereditary antithrombin deficiency ? | These resources address the diagnosis or management of hereditary antithrombin deficiency: - Genetic Testing Registry: Antithrombin III deficiency - MedlinePlus Encyclopedia: Blood Clots - MedlinePlus Encyclopedia: Congenital Antithrombin III 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 | hereditary antithrombin deficiency |
What is (are) glutathione synthetase deficiency ? | Glutathione synthetase deficiency is a disorder that prevents the production of an important molecule called glutathione. Glutathione helps prevent damage to cells by neutralizing harmful molecules generated during energy production. Glutathione also plays a role in processing medications and cancer-causing compounds (carcinogens), and building DNA, proteins, and other important cellular components. Glutathione synthetase deficiency can be classified into three types: mild, moderate, and severe. Mild glutathione synthetase deficiency usually results in the destruction of red blood cells (hemolytic anemia). In addition, affected individuals may release large amounts of a compound called 5-oxoproline in their urine (5-oxoprolinuria). This compound builds up when glutathione is not processed correctly in cells. Individuals with moderate glutathione synthetase deficiency may experience symptoms beginning shortly after birth including hemolytic anemia, 5-oxoprolinuria, and elevated acidity in the blood and tissues (metabolic acidosis). In addition to the features present in moderate glutathione synthetase deficiency, individuals affected by the severe form of this disorder may experience neurological symptoms. These problems may include seizures; a generalized slowing down of physical reactions, movements, and speech (psychomotor retardation); intellectual disability; and a loss of coordination (ataxia). Some people with severe glutathione synthetase deficiency also develop recurrent bacterial infections. | glutathione synthetase deficiency |
How many people are affected by glutathione synthetase deficiency ? | Glutathione synthetase deficiency is very rare. This disorder has been described in more than 70 people worldwide. | glutathione synthetase deficiency |
What are the genetic changes related to glutathione synthetase deficiency ? | Mutations in the GSS gene cause glutathione synthetase deficiency. The GSS gene provides instructions for making an enzyme called glutathione synthetase. This enzyme is involved in a process called the gamma-glutamyl cycle, which takes place in most of the body's cells. This cycle is necessary for producing a molecule called glutathione. Glutathione protects cells from damage caused by unstable oxygen-containing molecules, which are byproducts of energy production. Glutathione is called an antioxidant because of its role in protecting cells from the damaging effects of these unstable molecules. Mutations in the GSS gene prevent cells from making adequate levels of glutathione, leading to the signs and symptoms of glutathione synthetase deficiency. | glutathione synthetase deficiency |
Is glutathione synthetase 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. | glutathione synthetase deficiency |
What are the treatments for glutathione synthetase deficiency ? | These resources address the diagnosis or management of glutathione synthetase deficiency: - Baby's First Test - Genetic Testing Registry: Glutathione synthetase deficiency of erythrocytes, hemolytic anemia due to - Genetic Testing Registry: Gluthathione synthetase 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 | glutathione synthetase deficiency |
What is (are) palmoplantar keratoderma with deafness ? | Palmoplantar keratoderma with deafness is a disorder characterized by skin abnormalities and hearing loss. Affected individuals develop unusually thick skin on the palms of the hands and soles of the feet (palmoplantar keratoderma) beginning in childhood. Hearing loss ranges from mild to profound. It begins in early childhood and gets worse over time. Affected individuals have particular trouble hearing high-pitched sounds. The signs and symptoms of this disorder may vary even within the same family, with some individuals developing only skin abnormalities and others developing only hearing loss. | palmoplantar keratoderma with deafness |
How many people are affected by palmoplantar keratoderma with deafness ? | Palmoplantar keratoderma with deafness is a rare disorder; its prevalence is unknown. At least 10 affected families have been identified. | palmoplantar keratoderma with deafness |
What are the genetic changes related to palmoplantar keratoderma with deafness ? | Palmoplantar keratoderma with deafness can be caused by mutations in the GJB2 or MT-TS1 genes. The GJB2 gene provides instructions for making a protein called gap junction beta 2, more commonly known as connexin 26. Connexin 26 is a member of the connexin protein family. Connexin proteins form channels called gap junctions that permit the transport of nutrients, charged atoms (ions), and signaling molecules between neighboring cells that are in contact with each other. Gap junctions made with connexin 26 transport potassium ions and certain small molecules. Connexin 26 is found in cells throughout the body, including the inner ear and the skin. In the inner ear, channels made from connexin 26 are found in a snail-shaped structure called the cochlea. These channels may help to maintain the proper level of potassium ions required for the conversion of sound waves to electrical nerve impulses. This conversion is essential for normal hearing. In addition, connexin 26 may be involved in the maturation of certain cells in the cochlea. Connexin 26 also plays a role in the growth, maturation, and stability of the outermost layer of skin (the epidermis). The GJB2 gene mutations that cause palmoplantar keratoderma with deafness change single protein building blocks (amino acids) in connexin 26. The altered protein probably disrupts the function of normal connexin 26 in cells, and may interfere with the function of other connexin proteins. This disruption could affect skin growth and also impair hearing by disturbing the conversion of sound waves to nerve impulses. Palmoplantar keratoderma with deafness can also be caused by a mutation in the MT-TS1 gene. This gene provides instructions for making a particular type of RNA, a molecule that is a chemical cousin of DNA. This type of RNA, called transfer RNA (tRNA), helps assemble amino acids into full-length, functioning proteins. The MT-TS1 gene provides instructions for a specific form of tRNA that is designated as tRNASer(UCN). This molecule attaches to a particular amino acid, serine (Ser), and inserts it into the appropriate locations in many different proteins. The tRNASer(UCN) molecule is present only in cellular structures called mitochondria. These structures convert energy from food into a form that cells can use. Through a process called oxidative phosphorylation, mitochondria use oxygen, simple sugars, and fatty acids to create adenosine triphosphate (ATP), the cell's main energy source. The tRNASer(UCN) molecule is involved in the assembly of proteins that carry out oxidative phosphorylation. The MT-TS1 gene mutation that causes palmoplantar keratoderma with deafness leads to reduced levels of tRNASer(UCN) to assemble proteins within mitochondria. Reduced production of proteins needed for oxidative phosphorylation may impair the ability of mitochondria to make ATP. Researchers have not determined why the effects of the mutation are limited to cells in the inner ear and the skin in this condition. | palmoplantar keratoderma with deafness |
Is palmoplantar keratoderma with deafness inherited ? | Palmoplantar keratoderma with deafness can have different inheritance patterns. When this disorder is caused by GJB2 gene mutations, it is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family. When palmoplantar keratoderma with deafness is caused by mutations in the MT-TS1 gene, it is inherited in a mitochondrial pattern, which is also known as maternal inheritance. This pattern of inheritance applies to genes contained in mitochondrial DNA (mtDNA). Because egg cells, but not sperm cells, contribute mitochondria to the developing embryo, children can only inherit disorders resulting from mtDNA mutations from their mother. These disorders can appear in every generation of a family and can affect both males and females, but fathers do not pass traits associated with changes in mtDNA to their children. | palmoplantar keratoderma with deafness |
What are the treatments for palmoplantar keratoderma with deafness ? | These resources address the diagnosis or management of palmoplantar keratoderma with deafness: - Foundation for Ichthyosis and Related Skin Types: Palmoplantar Keratodermas - Genetic Testing Registry: Keratoderma palmoplantar deafness 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 | palmoplantar keratoderma with deafness |
What is (are) Crohn disease ? | Crohn disease is a complex, chronic disorder that primarily affects the digestive system. This condition typically involves abnormal inflammation of the intestinal walls, particularly in the lower part of the small intestine (the ileum) and portions of the large intestine (the colon). Inflammation can occur in any part of the digestive system, however. The inflamed tissues become thick and swollen, and the inner surface of the intestine may develop open sores (ulcers). Crohn disease most commonly appears in a person's late teens or twenties, although the disease can appear at any age. Signs and symptoms tend to flare up multiple times throughout life. The most common features of this condition are persistent diarrhea, abdominal pain and cramping, loss of appetite, weight loss, and fever. Some people with Crohn disease have chronic bleeding from inflamed tissues in the intestine; over time, this bleeding can lead to a low number of red blood cells (anemia). In some cases, Crohn disease can also cause medical problems affecting the joints, eyes, or skin. Intestinal blockage is a common complication of Crohn disease. Blockages are caused by swelling or a buildup of scar tissue in the intestinal walls. Some affected individuals also develop fistulae, which are abnormal connections between the intestine and other tissues. Fistulae occur when ulcers break through the intestinal wall to form passages between loops of the intestine or between the intestine and nearby structures (such as the bladder, vagina, or skin). Crohn disease is one common form of inflammatory bowel disease (IBD). Another type of IBD, ulcerative colitis, also causes chronic inflammation of the intestinal lining. Unlike Crohn disease, which can affect any part of the digestive system, ulcerative colitis typically causes inflammation only in the colon. In addition, the two disorders involve different patterns of inflammation. | Crohn disease |
How many people are affected by Crohn disease ? | Crohn disease is most common in western Europe and North America, where it affects 100 to 150 in 100,000 people. About one million Americans are currently affected by this disorder. Crohn disease occurs more often in whites and people of eastern and central European (Ashkenazi) Jewish descent than among people of other ethnic backgrounds. | Crohn disease |
What are the genetic changes related to Crohn disease ? | Crohn disease is related to chromosomes 5 and 10. Variations of the ATG16L1, IRGM, and NOD2 genes increase the risk of developing Crohn disease. The IL23R gene is associated with Crohn disease. A variety of genetic and environmental factors likely play a role in causing Crohn disease. Although researchers are studying risk factors that may contribute to this complex disorder, many of these factors remain unknown. Cigarette smoking is thought to increase the risk of developing this disease, and it may also play a role in periodic flare-ups of signs and symptoms. Studies suggest that Crohn disease may result from a combination of certain genetic variations, changes in the immune system, and the presence of bacteria in the digestive tract. Recent studies have identified variations in specific genes, including ATG16L1, IL23R, IRGM, and NOD2, that influence the risk of developing Crohn disease. These genes provide instructions for making proteins that are involved in immune system function. Variations in any of these genes may disrupt the ability of cells in the intestine to respond normally to bacteria. An abnormal immune response to bacteria in the intestinal walls may lead to chronic inflammation and the digestive problems characteristic of Crohn disease. Researchers have also discovered genetic variations in certain regions of chromosome 5 and chromosome 10 that appear to contribute to Crohn disease risk. One area of chromosome 5, known as the IBD5 locus, contains several genetic changes that may increase the risk of developing this condition. Other regions of chromosome 5 and chromosome 10 identified in studies of Crohn disease risk are known as "gene deserts" because they include no known genes. Instead, these regions may contain stretches of DNA that regulate nearby genes. Additional research is needed to determine how genetic variations in these chromosomal regions are related to a person's chance of developing Crohn disease. | Crohn disease |
Is Crohn disease inherited ? | The inheritance pattern of Crohn disease is unclear because many genetic and environmental factors are likely to be involved. This condition tends to cluster in families, however, and having an affected family member is a significant risk factor for the disease. | Crohn disease |
What are the treatments for Crohn disease ? | These resources address the diagnosis or management of Crohn disease: - Genetic Testing Registry: Inflammatory bowel disease 1 - MedlinePlus Encyclopedia: Crohn's 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 | Crohn disease |
What is (are) frontometaphyseal dysplasia ? | Frontometaphyseal dysplasia is a disorder involving abnormalities in skeletal development and other health problems. It is a member of a group of related conditions called otopalatodigital spectrum disorders, which also includes otopalatodigital syndrome type 1, otopalatodigital syndrome type 2, and Melnick-Needles syndrome. In general, these disorders involve hearing loss caused by malformations in the tiny bones in the ears (ossicles), problems in the development of the roof of the mouth (palate), and skeletal abnormalities involving the fingers and/or toes (digits). Frontometaphyseal dysplasia is distinguished from the other otopalatodigital spectrum disorders by the presence of joint deformities called contractures that restrict the movement of certain joints. People with frontometaphyseal dysplasia may also have bowed limbs, an abnormal curvature of the spine (scoliosis), and abnormalities of the fingers and hands. Characteristic facial features may include prominent brow ridges; wide-set and downward-slanting eyes; a very small lower jaw and chin (micrognathia); and small, missing or misaligned teeth. Some affected individuals have hearing loss. In addition to skeletal abnormalities, individuals with frontometaphyseal dysplasia may have obstruction of the ducts between the kidneys and bladder (ureters), heart defects, or constrictions in the passages leading from the windpipe to the lungs (the bronchi) that can cause problems with breathing. Males with frontometaphyseal dysplasia generally have more severe signs and symptoms of the disorder than do females, who may show only the characteristic facial features. | frontometaphyseal dysplasia |
How many people are affected by frontometaphyseal dysplasia ? | Frontometaphyseal dysplasia is a rare disorder; only a few dozen cases have been reported worldwide. | frontometaphyseal dysplasia |
What are the genetic changes related to frontometaphyseal dysplasia ? | Mutations in the FLNA gene cause frontometaphyseal dysplasia. The FLNA gene provides instructions for producing the protein filamin A, which helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Filamin A binds to another protein called actin, and helps the actin to form the branching network of filaments that make up the cytoskeleton. Filamin A also links actin to many other proteins to perform various functions within the cell. A small number of mutations in the FLNA gene have been identified in people with frontometaphyseal dysplasia. These mutations are described as "gain-of-function" because they appear to enhance the activity of the filamin A protein or give the protein a new, atypical function. Researchers believe that the mutations may change the way the filamin A protein helps regulate processes involved in skeletal development, but it is not known how changes in the protein relate to the specific signs and symptoms of frontometaphyseal dysplasia. | frontometaphyseal dysplasia |
Is frontometaphyseal dysplasia inherited ? | This condition is inherited in an X-linked dominant pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In females (who have two X chromosomes), a mutation in one of the two copies of the gene in each cell is sufficient to cause the disorder. In males (who have only one X chromosome), a mutation in the only copy of the gene in each cell causes the disorder. In most cases, males experience more severe symptoms of the disorder than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. | frontometaphyseal dysplasia |
What are the treatments for frontometaphyseal dysplasia ? | These resources address the diagnosis or management of frontometaphyseal dysplasia: - Gene Review: Gene Review: Otopalatodigital Spectrum Disorders - Genetic Testing Registry: Frontometaphyseal 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 | frontometaphyseal dysplasia |
What is (are) recombinant 8 syndrome ? | Recombinant 8 syndrome is a condition that involves heart and urinary tract abnormalities, moderate to severe intellectual disability, and a distinctive facial appearance. The characteristic facial features include a wide, square face; a thin upper lip; a downturned mouth; a small chin (micrognathia); wide-set eyes (hypertelorism); and low-set or unusually shaped ears. People with recombinant 8 syndrome may have overgrowth of the gums (gingival hyperplasia) and abnormal tooth development. Males with this condition frequently have undescended testes (cryptorchidism). Some affected individuals have recurrent ear infections (otitis media) or hearing loss. Many children with recombinant 8 syndrome do not survive past early childhood, usually due to complications related to their heart abnormalities. | recombinant 8 syndrome |
How many people are affected by recombinant 8 syndrome ? | Recombinant 8 syndrome is a rare condition; its exact incidence is unknown. Most people with this condition are descended from a Hispanic population originating in the San Luis Valley area of southern Colorado and northern New Mexico. Recombinant 8 syndrome is also called San Luis Valley syndrome. Only a few cases outside this population have been found. | recombinant 8 syndrome |
What are the genetic changes related to recombinant 8 syndrome ? | Recombinant 8 syndrome is caused by a rearrangement of chromosome 8 that results in a deletion of a piece of the short (p) arm and a duplication of a piece of the long (q) arm. The deletion and duplication result in the recombinant 8 chromosome. The signs and symptoms of recombinant 8 syndrome are related to the loss and addition of genetic material on these regions of chromosome 8. Researchers are working to determine which genes are involved in the deletion and duplication on chromosome 8. | recombinant 8 syndrome |
Is recombinant 8 syndrome inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the recombinant chromosome 8 in each cell is sufficient to cause the disorder. Most people with recombinant 8 syndrome have at least one parent with a change in chromosome 8 called an inversion. An inversion involves the breakage of a chromosome in two places; the resulting piece of DNA is reversed and reinserted into the chromosome. Genetic material is typically not lost as a result of this inversion in chromosome 8, so people usually do not have any related health problems. However, genetic material can be lost or duplicated when inversions are being passed to the next generation. People with this chromosome 8 inversion are at of risk having a child with recombinant 8 syndrome. | recombinant 8 syndrome |
What are the treatments for recombinant 8 syndrome ? | These resources address the diagnosis or management of recombinant 8 syndrome: - Genetic Testing Registry: Recombinant chromosome 8 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 | recombinant 8 syndrome |
What is (are) biotin-thiamine-responsive basal ganglia disease ? | Biotin-thiamine-responsive basal ganglia disease is a disorder that affects the nervous system, including a group of structures in the brain called the basal ganglia, which help control movement. As its name suggests, the condition may improve if the vitamins biotin and thiamine are given as treatment. Without early and lifelong vitamin treatment, people with biotin-thiamine-responsive basal ganglia disease experience a variety of neurological problems that gradually get worse. The occurrence of specific neurological problems and their severity vary even among affected individuals within the same family. The signs and symptoms of biotin-thiamine-responsive basal ganglia disease usually begin between the ages of 3 and 10, but the disorder can appear at any age. Many of the neurological problems that can occur in biotin-thiamine-responsive basal ganglia disease affect movement, and can include involuntary tensing of various muscles (dystonia), muscle rigidity, muscle weakness on one or both sides of the body (hemiparesis or quadriparesis), problems coordinating movements (ataxia), and exaggerated reflexes (hyperreflexia). Movement problems can also affect the face, and may include the inability to move facial muscles due to facial nerve paralysis (supranuclear facial palsy), paralysis of the eye muscles (external ophthalmoplegia), difficulty chewing or swallowing (dysphagia), and slurred speech. Affected individuals may also experience confusion, loss of previously learned skills, intellectual disability, and seizures. Severe cases may result in coma and become life-threatening. Typically, the neurological symptoms occur as increasingly severe episodes, which may be triggered by fever, injury, or other stresses on the body. Less commonly, the signs and symptoms persist at the same level or slowly increase in severity over time rather than occurring as episodes that come and go. In these individuals, the neurological problems are usually limited to dystonia, seizure disorders, and delay in the development of mental and motor skills (psychomotor delay). | biotin-thiamine-responsive basal ganglia disease |
How many people are affected by biotin-thiamine-responsive basal ganglia disease ? | Biotin-thiamine-responsive basal ganglia disease is a rare disorder; its prevalence is unknown. Approximately 48 cases have been reported in the medical literature; most of these are individuals from Arab populations. | biotin-thiamine-responsive basal ganglia disease |
What are the genetic changes related to biotin-thiamine-responsive basal ganglia disease ? | Biotin-thiamine-responsive basal ganglia disease is caused by mutations in the SLC19A3 gene. This gene provides instructions for making a protein called a thiamine transporter, which moves thiamine into cells. Thiamine, also known as vitamin B1, is obtained from the diet and is necessary for proper functioning of the nervous system. Mutations in the SLC19A3 gene likely result in a protein with impaired ability to transport thiamine into cells, resulting in decreased absorption of the vitamin and leading to neurological dysfunction. In this disorder, abnormalities affect several parts of the brain. Using medical imaging, generalized swelling as well as specific areas of damage (lesions) in the brain can often be seen, including in the basal ganglia. The relationship between these specific brain abnormalities and the abnormal thiamine transporter is unknown. It is unclear how biotin is related to this disorder. Some researchers suggest that the excess biotin given along with thiamine as treatment for the disorder may increase the amount of thiamine transporter that is produced, partially compensating for the impaired efficiency of the abnormal protein. Others propose that biotin transporter proteins may interact with thiamine transporters in such a way that biotin levels influence the course of the disease. | biotin-thiamine-responsive basal ganglia disease |
Is biotin-thiamine-responsive basal ganglia 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. | biotin-thiamine-responsive basal ganglia disease |
What are the treatments for biotin-thiamine-responsive basal ganglia disease ? | These resources address the diagnosis or management of biotin-thiamine-responsive basal ganglia disease: - Gene Review: Gene Review: Biotin-Thiamine-Responsive Basal Ganglia 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 | biotin-thiamine-responsive basal ganglia disease |
What is (are) congenital myasthenic syndrome ? | Congenital myasthenic syndrome is a group of conditions characterized by muscle weakness (myasthenia) that worsens with physical exertion. The muscle weakness typically begins in early childhood but can also appear in adolescence or adulthood. Facial muscles, including muscles that control the eyelids, muscles that move the eyes, and muscles used for chewing and swallowing, are most commonly affected. However, any of the muscles used for movement (skeletal muscles) can be affected in this condition. Due to muscle weakness, affected infants may have feeding difficulties. Development of motor skills such as crawling or walking may be delayed. The severity of the myasthenia varies greatly, with some people experiencing minor weakness and others having such severe weakness that they are unable to walk. Some individuals have episodes of breathing problems that may be triggered by fevers or infection. Severely affected individuals may also experience short pauses in breathing (apnea) that can lead to a bluish appearance of the skin or lips (cyanosis). | congenital myasthenic syndrome |
How many people are affected by congenital myasthenic syndrome ? | The prevalence of congenital myasthenic syndrome is unknown. At least 600 families with affected individuals have been described in the scientific literature. | congenital myasthenic syndrome |
What are the genetic changes related to congenital myasthenic syndrome ? | Mutations in many genes can cause congenital myasthenic syndrome. Mutations in the CHRNE gene are responsible for more than half of all cases. A large number of cases are also caused by mutations in the RAPSN, CHAT, COLQ, and DOK7 genes. All of these genes provide instructions for producing proteins that are involved in the normal function of the neuromuscular junction. The neuromuscular junction is the area between the ends of nerve cells and muscle cells where signals are relayed to trigger muscle movement. Gene mutations lead to changes in proteins that play a role in the function of the neuromuscular junction and disrupt signaling between the ends of nerve cells and muscle cells. Disrupted signaling between these cells results in an impaired ability to move skeletal muscles, muscle weakness, and delayed development of motor skills. The respiratory problems in congenital myasthenic syndrome result from impaired movement of the muscles of the chest wall and the muscle that separates the abdomen from the chest cavity (the diaphragm). Mutations in other genes that provide instructions for proteins involved in neuromuscular signaling have been found to cause some cases of congenital myasthenic syndrome, although these mutations account for only a small number of cases. Some people with congenital myasthenic syndrome do not have an identified mutation in any of the genes known to be associated with this condition. | congenital myasthenic syndrome |
Is congenital myasthenic syndrome inherited ? | This condition is most commonly 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. Rarely, 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 some cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family. | congenital myasthenic syndrome |
What are the treatments for congenital myasthenic syndrome ? | These resources address the diagnosis or management of congenital myasthenic syndrome: - Gene Review: Gene Review: Congenital Myasthenic Syndromes - Genetic Testing Registry: CHRNA1-Related Congenital Myasthenic Syndrome - Genetic Testing Registry: Congenital myasthenic syndrome - Genetic Testing Registry: Congenital myasthenic syndrome 1B, fast-channel - Genetic Testing Registry: Congenital myasthenic syndrome with tubular aggregates 1 - Genetic Testing Registry: Congenital myasthenic syndrome, acetazolamide-responsive - Genetic Testing Registry: Endplate acetylcholinesterase deficiency - Genetic Testing Registry: Familial infantile myasthenia - Genetic Testing Registry: Myasthenia, limb-girdle, familial - Genetic Testing Registry: Myasthenic syndrome, congenital, associated with acetylcholine receptor deficiency - Genetic Testing Registry: Myasthenic syndrome, slow-channel congenital These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | congenital myasthenic syndrome |
What is (are) tetrahydrobiopterin deficiency ? | Tetrahydrobiopterin deficiency is a rare disorder characterized by a shortage (deficiency) of a molecule called tetrahydrobiopterin or BH4. This condition alters the levels of several substances in the body, including phenylalanine. Phenylalanine is a building block of proteins (an amino acid) that is obtained through the diet. It is found in foods that contain protein and in some artificial sweeteners. High levels of phenylalanine are present from early infancy in people with untreated tetrahydrobiopterin deficiency. This condition also alters the levels of chemicals called neurotransmitters, which transmit signals between nerve cells in the brain. Infants with tetrahydrobiopterin deficiency appear normal at birth, but medical problems ranging from mild to severe become apparent over time. Signs and symptoms of this condition can include intellectual disability, progressive problems with development, movement disorders, difficulty swallowing, seizures, behavioral problems, and an inability to control body temperature. | tetrahydrobiopterin deficiency |
How many people are affected by tetrahydrobiopterin deficiency ? | This condition is rare, affecting an estimated 1 in 500,000 to 1 in 1 million newborns. In most parts of the world, tetrahydrobiopterin deficiency accounts for 1 to 3 percent of all cases of elevated phenylalanine levels. The remaining cases are caused by a similar condition called phenylketonuria (PKU). In certain countries, including Saudi Arabia, Taiwan, China, and Turkey, it is more common for elevated levels of phenylalanine to be caused by tetrahydrobiopterin deficiency than by PKU. | tetrahydrobiopterin deficiency |
What are the genetic changes related to tetrahydrobiopterin deficiency ? | Tetrahydrobiopterin deficiency can be caused by mutations in one of several genes, including GCH1, PCBD1, PTS, and QDPR. These genes provide instructions for making enzymes that help produce and recycle tetrahydrobiopterin in the body. Tetrahydrobiopterin normally helps process several amino acids, including phenylalanine. It is also involved in the production of neurotransmitters. If one of the enzymes fails to function correctly because of a gene mutation, little or no tetrahydrobiopterin is available to help process phenylalanine. As a result, phenylalanine can build up in the blood and other tissues. Because nerve cells in the brain are particularly sensitive to phenylalanine levels, excessive amounts of this substance can cause brain damage. Tetrahydrobiopterin deficiency can also alter the levels of certain neurotransmitters, which disrupts normal brain function. These abnormalities underlie the intellectual disability and other characteristic features of the condition. | tetrahydrobiopterin deficiency |
Is tetrahydrobiopterin 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. | tetrahydrobiopterin deficiency |
What are the treatments for tetrahydrobiopterin deficiency ? | These resources address the diagnosis or management of tetrahydrobiopterin deficiency: - Baby's First Test: Biopterin Defect in Cofactor Biosynthesis - Baby's First Test: Biopterin Defect in Cofactor Regeneration - Genetic Testing Registry: 6-pyruvoyl-tetrahydropterin synthase deficiency - Genetic Testing Registry: Dihydropteridine reductase deficiency - Genetic Testing Registry: GTP cyclohydrolase I deficiency - Genetic Testing Registry: Hyperphenylalaninemia, BH4-deficient, D - MedlinePlus Encyclopedia: Serum Phenylalanine Screening 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 | tetrahydrobiopterin deficiency |
What is (are) glycogen storage disease type V ? | Glycogen storage disease type V (also known as GSDV or McArdle disease) is an inherited disorder caused by an inability to break down a complex sugar called glycogen in muscle cells. A lack of glycogen breakdown interferes with the function of muscle cells. People with GSDV typically experience fatigue, muscle pain, and cramps during the first few minutes of exercise (exercise intolerance). Exercise such as weight lifting or jogging usually triggers these symptoms in affected individuals. The discomfort is generally alleviated with rest. If individuals rest after brief exercise and wait for their pain to go away, they can usually resume exercising with little or no discomfort (a characteristic phenomenon known as "second wind"). Prolonged or intense exercise can cause muscle damage in people with GSDV. About half of people with GSDV experience breakdown of muscle tissue (rhabdomyolysis). In severe episodes, the destruction of muscle tissue releases a protein called myoglobin, which is filtered through the kidneys and released in the urine (myoglobinuria). Myoglobin causes the urine to be red or brown. This protein can also damage the kidneys, and it is estimated that half of those individuals with GSDV who have myoglobinuria will develop life-threatening kidney failure. The signs and symptoms of GSDV can vary significantly in affected individuals. The features of this condition typically begin in a person's teens or twenties, but they can appear anytime from infancy to adulthood. In most people with GSDV, the muscle weakness worsens over time; however, in about one-third of affected individuals, the muscle weakness is stable. Some people with GSDV experience mild symptoms such as poor stamina; others do not experience any symptoms. | glycogen storage disease type V |
How many people are affected by glycogen storage disease type V ? | GSDV is a rare disorder; however, its prevalence is unknown. In the Dallas-Fort Worth area of Texas, where the prevalence of GSDV has been studied, the condition is estimated to affect 1 in 100,000 individuals. | glycogen storage disease type V |
What are the genetic changes related to glycogen storage disease type V ? | Mutations in the PYGM gene cause GSDV. The PYGM gene provides instructions for making an enzyme called myophosphorylase. This enzyme is found only in muscle cells, where it breaks down glycogen into a simpler 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. PYGM gene mutations prevent myophosphorylase from breaking down glycogen effectively. As a result, muscle cells cannot produce enough energy, so muscles become easily fatigued. Reduced energy production in muscle cells leads to the major features of GSDV. | glycogen storage disease type V |
Is glycogen storage disease type V 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 V |
What are the treatments for glycogen storage disease type V ? | These resources address the diagnosis or management of glycogen storage disease type V: - Gene Review: Gene Review: Glycogen Storage Disease Type V - Genetic Testing Registry: Glycogen storage disease, type V - MedlinePlus Encyclopedia: McArdle 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 | glycogen storage disease type V |
What is (are) dyskeratosis congenita ? | Dyskeratosis congenita is a disorder that can affect many parts of the body. There are three features that are characteristic of this disorder: fingernails and toenails that grow poorly or are abnormally shaped (nail dystrophy); changes in skin coloring (pigmentation), especially on the neck and chest, in a pattern often described as "lacy"; and white patches inside the mouth (oral leukoplakia). People with dyskeratosis congenita have an increased risk of developing several life-threatening conditions. They are especially vulnerable to disorders that impair bone marrow function. These disorders disrupt the ability of the bone marrow to produce new blood cells. Affected individuals may develop aplastic anemia, also known as bone marrow failure, which occurs when the bone marrow does not produce enough new blood cells. They are also at higher than average risk for myelodysplastic syndrome, a condition in which immature blood cells fail to develop normally; this condition may progress to a form of blood cancer called leukemia. People with dyskeratosis congenita are also at increased risk of developing leukemia even if they never develop myelodysplastic syndrome. In addition, they have a higher than average risk of developing other cancers, especially cancers of the head, neck, anus, or genitals. People with dyskeratosis congenita may also develop pulmonary fibrosis, a condition that causes scar tissue (fibrosis) to build up in the lungs, decreasing the transport of oxygen into the bloodstream. Additional signs and symptoms that occur in some people with dyskeratosis congenita include eye abnormalities such as narrow tear ducts that may become blocked, preventing drainage of tears and leading to eyelid irritation; dental problems; hair loss or prematurely grey hair; low bone mineral density (osteoporosis); degeneration (avascular necrosis) of the hip and shoulder joints; or liver disease. Some affected males may have narrowing (stenosis) of the urethra, which is the tube that carries urine out of the body from the bladder. Urethral stenosis may lead to difficult or painful urination and urinary tract infections. The severity of dyskeratosis congenita varies widely among affected individuals. The least severely affected individuals have only a few mild physical features of the disorder and normal bone marrow function. More severely affected individuals have many of the characteristic physical features and experience bone marrow failure, cancer, or pulmonary fibrosis by early adulthood. While most people with dyskeratosis congenita have normal intelligence and development of motor skills such as standing and walking, developmental delay may occur in some severely affected individuals. In one severe form of the disorder called Hoyeraal Hreidaarsson syndrome, affected individuals have an unusually small and underdeveloped cerebellum, which is the part of the brain that coordinates movement. Another severe variant called Revesz syndrome involves abnormalities in the light-sensitive tissue at the back of the eye (retina) in addition to the other symptoms of dyskeratosis congenita. | dyskeratosis congenita |
How many people are affected by dyskeratosis congenita ? | The exact prevalence of dyskeratosis congenita is unknown. It is estimated to occur in approximately 1 in 1 million people. | dyskeratosis congenita |
What are the genetic changes related to dyskeratosis congenita ? | In about half of people with dyskeratosis congenita, the disorder is caused by mutations in the TERT, TERC, DKC1, or TINF2 gene. These genes provide instructions for making proteins that help maintain structures known as telomeres, which are found at the ends of chromosomes. In a small number of individuals with dyskeratosis congenita, mutations in other genes involved with telomere maintenance have been identified. Other affected individuals have no mutations in any of the genes currently associated with dyskeratosis congenita. In these cases, the cause of the disorder is unknown, but other unidentified genes related to telomere maintenance are likely involved. Telomeres help protect chromosomes from abnormally sticking together or breaking down (degrading). In most cells, telomeres become progressively shorter as the cell divides. After a certain number of cell divisions, the telomeres become so short that they trigger the cell to stop dividing or to self-destruct (undergo apoptosis). Telomeres are maintained by two important protein complexes called telomerase and shelterin. Telomerase helps maintain normal telomere length by adding small repeated segments of DNA to the ends of chromosomes each time the cell divides. The main components of telomerase, called hTR and hTERT, are produced from the TERC and TERT genes, respectively. The hTR component is an RNA molecule, a chemical cousin of DNA. It provides a template for creating the repeated sequence of DNA that telomerase adds to the ends of chromosomes. The function of the hTERT component is to add the new DNA segment to chromosome ends. The DKC1 gene provides instructions for making another protein that is important in telomerase function. This protein, called dyskerin, attaches (binds) to hTR and helps stabilize the telomerase complex. The shelterin complex helps protect telomeres from the cell's DNA repair process. Without the protection of shelterin, the repair mechanism would sense the chromosome ends as abnormal breaks in the DNA sequence and either attempt to join the ends together or initiate apoptosis. The TINF2 gene provides instructions for making a protein that is part of the shelterin complex. TERT, TERC, DKC1, or TINF2 gene mutations result in dysfunction of the telomerase or shelterin complexes, leading to impaired maintenance of telomeres and reduced telomere length. Cells that divide rapidly are especially vulnerable to the effects of shortened telomeres. As a result, people with dyskeratosis congenita may experience a variety of problems affecting quickly dividing cells in the body such as cells of the nail beds, hair follicles, skin, lining of the mouth (oral mucosa), and bone marrow. Breakage and instability of chromosomes resulting from inadequate telomere maintenance may lead to genetic changes that allow cells to divide in an uncontrolled way, resulting in the development of cancer in people with dyskeratosis congenita. | dyskeratosis congenita |
Is dyskeratosis congenita inherited ? | Dyskeratosis congenita can have different inheritance patterns. When dyskeratosis congenita is caused by DKC1 gene mutations, it is inherited in an X-linked recessive pattern. The DKC1 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. When dyskeratosis congenita is caused by mutations in other genes, it can be inherited in an autosomal dominant or autosomal recessive pattern. Autosomal dominant means one copy of the altered gene in each cell is sufficient to cause the disorder. Autosomal recessive 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. | dyskeratosis congenita |
What are the treatments for dyskeratosis congenita ? | These resources address the diagnosis or management of dyskeratosis congenita: - Gene Review: Gene Review: Dyskeratosis Congenita - Genetic Testing Registry: Dyskeratosis congenita - Genetic Testing Registry: Dyskeratosis congenita X-linked - Genetic Testing Registry: Dyskeratosis congenita autosomal dominant - Genetic Testing Registry: Dyskeratosis congenita autosomal recessive 1 - Seattle Children's Hospital 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 | dyskeratosis congenita |
What is (are) familial encephalopathy with neuroserpin inclusion bodies ? | Familial encephalopathy with neuroserpin inclusion bodies (FENIB) is a disorder that causes progressive dysfunction of the brain (encephalopathy). It is characterized by a loss of intellectual functioning (dementia) and seizures. At first, affected individuals may have difficulty sustaining attention and concentrating. They may experience repetitive thoughts, speech, or movements. As the condition progresses, their personality changes and judgment, insight, and memory become impaired. Affected people lose the ability to perform the activities of daily living, and most eventually require comprehensive care. The signs and symptoms of FENIB vary in their severity and age of onset. In severe cases, the condition causes seizures and episodes of sudden, involuntary muscle jerking or twitching (myoclonus) in addition to dementia. These signs can appear as early as a person's teens. Less severe cases are characterized by a progressive decline in intellectual functioning beginning in a person's forties or fifties. | familial encephalopathy with neuroserpin inclusion bodies |
How many people are affected by familial encephalopathy with neuroserpin inclusion bodies ? | This condition appears to be rare; only a few affected individuals have been reported worldwide. | familial encephalopathy with neuroserpin inclusion bodies |
What are the genetic changes related to familial encephalopathy with neuroserpin inclusion bodies ? | FENIB results from mutations in the SERPINI1 gene. This gene provides instructions for making a protein called neuroserpin, which is found in nerve cells (neurons). Neuroserpin plays a role in the development and function of the nervous system. This protein helps control the growth of neurons and their connections with one another, which suggests that it may be important for learning and memory. Mutations in the SERPINI1 gene result in the production of an abnormally shaped, unstable form of neuroserpin. Within neurons, defective neuroserpin proteins can attach to one another and form clumps called neuroserpin inclusion bodies or Collins bodies. These clumps disrupt the cells' normal functioning and ultimately lead to cell death. The gradual loss of neurons in certain parts of the brain causes progressive dementia. Researchers believe that a buildup of related, potentially toxic substances in neurons may also contribute to the signs and symptoms of this condition. | familial encephalopathy with neuroserpin inclusion bodies |
Is familial encephalopathy with neuroserpin inclusion bodies inherited ? | FENIB 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 many cases, an affected person has a parent with the condition. | familial encephalopathy with neuroserpin inclusion bodies |
What are the treatments for familial encephalopathy with neuroserpin inclusion bodies ? | These resources address the diagnosis or management of FENIB: - Genetic Testing Registry: Familial encephalopathy with neuroserpin inclusion bodies - MedlinePlus Encyclopedia: Dementia - MedlinePlus Encyclopedia: Seizures 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 encephalopathy with neuroserpin inclusion bodies |
What is (are) craniofacial-deafness-hand syndrome ? | Craniofacial-deafness-hand syndrome is characterized by distinctive facial features, profound hearing loss, and hand abnormalities. The distinctive facial features of people with craniofacial-deafness-hand syndrome result from a variety of developmental abnormalities involving the skull (cranium) and face. Affected individuals often have underdeveloped or absent nasal bones resulting in a small nose, thin nostrils, and a flattened mid-face with a flat nasal bridge. Individuals with this condition typically also have widely spaced eyes (ocular hypertelorism), narrowed openings of the eyes (narrowed palpebral fissures), a small upper jaw (hypoplastic maxilla), and a small mouth with pursed lips. People with this condition also have profound hearing loss that is caused by abnormalities in the inner ear (sensorineural deafness). Hearing loss in these individuals is present from birth. In affected individuals, a common abnormality of the muscles in the hand is a malformation in which all of the fingers are angled outward toward the fifth finger (ulnar deviation). People with craniofacial-deafness-hand syndrome may also have permanently bent third, fourth, and fifth fingers (camptodactyly), which can limit finger movement and lead to joint deformities called contractures. Contractures in the wrist can further impair hand movements. | craniofacial-deafness-hand syndrome |
How many people are affected by craniofacial-deafness-hand syndrome ? | Craniofacial-deafness-hand syndrome is an extremely rare condition. Only a few cases have been reported in the scientific literature. | craniofacial-deafness-hand syndrome |
What are the genetic changes related to craniofacial-deafness-hand syndrome ? | Craniofacial-deafness-hand syndrome is caused by mutations in the PAX3 gene. The PAX3 gene plays a critical role in the formation of tissues and organs during embryonic development. To perform this function, the gene provides instructions for making a protein that attaches (binds) to specific areas of DNA to help control the activity of particular genes. During embryonic development, the PAX3 gene is active in cells called neural crest cells. These cells migrate from the developing spinal cord to specific regions in the embryo. The protein produced from the PAX3 gene directs the activity of other genes that signal neural crest cells to form specialized tissues or cell types. These include some nerve tissues, bones in the face and skull (craniofacial bones), and muscle tissue. At least one PAX3 gene mutation has been identified in individuals with craniofacial-deafness-hand syndrome. This mutation appears to affect the ability of the PAX3 protein to bind to DNA. As a result, the PAX3 protein cannot control the activity of other genes and cannot regulate the differentiation of neural crest cells. A lack of specialization of neural crest cells leads to the impaired growth of craniofacial bones, nerve tissue, and muscles seen in craniofacial-deafness-hand syndrome. | craniofacial-deafness-hand syndrome |
Is craniofacial-deafness-hand 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. | craniofacial-deafness-hand syndrome |
What are the treatments for craniofacial-deafness-hand syndrome ? | These resources address the diagnosis or management of craniofacial-deafness-hand syndrome: - Genetic Testing Registry: Craniofacial deafness hand syndrome - Johns Hopkins Children's Center: Hearing Loss 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 | craniofacial-deafness-hand syndrome |
What is (are) Apert syndrome ? | Apert syndrome is a genetic disorder characterized by the premature fusion of certain skull bones (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face. In addition, a varied number of fingers and toes are fused together (syndactyly). Many of the characteristic facial features of Apert syndrome result from the premature fusion of the skull bones. The head is unable to grow normally, which leads to a sunken appearance in the middle of the face, bulging and wide-set eyes, a beaked nose, and an underdeveloped upper jaw leading to crowded teeth and other dental problems. Shallow eye sockets can cause vision problems. Early fusion of the skull bones also affects the development of the brain, which can disrupt intellectual development. Cognitive abilities in people with Apert syndrome range from normal to mild or moderate intellectual disability. Individuals with Apert syndrome have webbed or fused fingers and toes. The severity of the fusion varies; at a minimum, three digits on each hand and foot are fused together. In the most severe cases, all of the fingers and toes are fused. Less commonly, people with this condition may have extra fingers or toes (polydactyly). Additional signs and symptoms of Apert syndrome can include hearing loss, unusually heavy sweating (hyperhidrosis), oily skin with severe acne, patches of missing hair in the eyebrows, fusion of spinal bones in the neck (cervical vertebrae), and recurrent ear infections that may be associated with an opening in the roof of the mouth (a cleft palate). | Apert syndrome |
How many people are affected by Apert syndrome ? | Apert syndrome affects an estimated 1 in 65,000 to 88,000 newborns. | Apert syndrome |
What are the genetic changes related to Apert syndrome ? | Mutations in the FGFR2 gene cause Apert syndrome. This gene produces a protein called fibroblast growth factor receptor 2. Among its multiple functions, this protein signals immature cells to become bone cells during embryonic development. A mutation in a specific part of the FGFR2 gene alters the protein and causes prolonged signaling, which can promote the premature fusion of bones in the skull, hands, and feet. | Apert syndrome |
Is Apert syndrome inherited ? | Apert syndrome is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Almost all cases of Apert syndrome result from new mutations in the gene, and occur in people with no history of the disorder in their family. Individuals with Apert syndrome, however, can pass along the condition to the next generation. | Apert syndrome |
What are the treatments for Apert syndrome ? | These resources address the diagnosis or management of Apert syndrome: - Gene Review: Gene Review: FGFR-Related Craniosynostosis Syndromes - Genetic Testing Registry: Acrocephalosyndactyly type I - MedlinePlus Encyclopedia: Apert syndrome - MedlinePlus Encyclopedia: Webbing of the fingers or toes These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Apert syndrome |
What is (are) adult polyglucosan body disease ? | Adult polyglucosan body disease is a condition that affects the nervous system. People with this condition have problems walking due to reduced sensation in their legs (peripheral neuropathy) and progressive muscle weakness and stiffness (spasticity). Damage to the nerves that control bladder function, a condition called neurogenic bladder, causes affected individuals to have progressive difficulty controlling the flow of urine. About half of people with adult polyglucosan body disease experience a decline in intellectual function (dementia). People with adult polyglucosan body disease typically first experience signs and symptoms related to the condition between ages 30 and 60. | adult polyglucosan body disease |
How many people are affected by adult polyglucosan body disease ? | Adult polyglucosan body disease is a rare condition; although its exact prevalence is unknown, at least 50 affected individuals have been described in the medical literature. | adult polyglucosan body disease |
What are the genetic changes related to adult polyglucosan body disease ? | Mutations in the GBE1 gene cause adult polyglucosan body disease. The GBE1 gene provides instructions for making the glycogen branching enzyme. This enzyme is involved in the production of a complex sugar called glycogen, which is a major source of stored energy in the body. Most GBE1 gene mutations result in a shortage (deficiency) of the glycogen branching enzyme, which leads to the production of abnormal glycogen molecules. These abnormal glycogen molecules, called polyglucosan bodies, accumulate within cells and cause damage. Nerve cells (neurons) appear to be particularly vulnerable to the accumulation of polyglucosan bodies in people with this disorder, leading to impaired neuronal function. Some mutations in the GBE1 gene that cause adult polyglucosan body disease do not result in a shortage of glycogen branching enzyme. In people with these mutations, the activity of this enzyme is normal. How mutations cause the disease in these individuals is unclear. Other people with adult polyglucosan body disease do not have identified mutations in the GBE1 gene. In these individuals, the cause of the disease is unknown. | adult polyglucosan body disease |
Is adult polyglucosan body 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. | adult polyglucosan body disease |
What are the treatments for adult polyglucosan body disease ? | These resources address the diagnosis or management of adult polyglucosan body disease: - Gene Review: Gene Review: Adult Polyglucosan Body Disease - Genetic Testing Registry: Polyglucosan body disease, adult - MedlinePlus Encyclopedia: Neurogenic Bladder - MedlinePlus Encyclopedia: Spasticity 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 | adult polyglucosan body disease |
What is (are) X-linked chondrodysplasia punctata 2 ? | X-linked chondrodysplasia punctata 2 is a disorder characterized by bone, skin, and eye abnormalities. It occurs almost exclusively in females. Although the signs and symptoms of this condition vary widely, almost all affected individuals have chondrodysplasia punctata, an abnormality that appears on x-rays as spots (stippling) near the ends of bones and in cartilage. In this form of chondrodysplasia punctata, the stippling typically affects the long bones in the arms and legs, the ribs, the spinal bones (vertebrae), and the cartilage that makes up the windpipe (trachea). The stippling is apparent in infancy but disappears in early childhood. Other skeletal abnormalities seen in people with X-linked chondrodysplasia punctata 2 include shortening of the bones in the upper arms and thighs (rhizomelia) that is often different on the right and left sides, and progressive abnormal curvature of the spine (kyphoscoliosis). As a result of these abnormalities, people with this condition tend to have short stature. Infants with X-linked chondrodysplasia punctata 2 are born with dry, scaly patches of skin (ichthyosis) in a linear or spiral (whorled) pattern. The scaly patches fade over time, leaving abnormally colored blotches of skin without hair (follicular atrophoderma). Most affected individuals also have sparse, coarse hair on their scalps. Most people with X-linked chondrodysplasia punctata 2 have clouding of the lens of the eye (cataracts) from birth or early childhood. Other eye abnormalities that have been associated with this disorder include unusually small eyes (microphthalmia) and small corneas (microcornea). The cornea is the clear front surface of the eye. These eye abnormalities can impair vision. In affected females, X-linked chondrodysplasia punctata 2 is typically associated with normal intelligence and a normal lifespan. However, a much more severe form of the condition has been reported in a small number of males. Affected males have some of the same features as affected females, as well as weak muscle tone (hypotonia), changes in the structure of the brain, moderately to profoundly delayed development, seizures, distinctive facial features, and other birth defects. The health problems associated with X-linked chondrodysplasia punctata 2 are often life-threatening in males. | X-linked chondrodysplasia punctata 2 |
How many people are affected by X-linked chondrodysplasia punctata 2 ? | X-linked chondrodysplasia punctata 2 has been estimated to affect fewer than 1 in 400,000 newborns. However, the disorder may actually be more common than this estimate because it is likely underdiagnosed, particularly in females with mild signs and symptoms. More than 95 percent of cases of X-linked chondrodysplasia punctata 2 occur in females. About a dozen males with the condition have been reported in the scientific literature. | X-linked chondrodysplasia punctata 2 |
What are the genetic changes related to X-linked chondrodysplasia punctata 2 ? | X-linked chondrodysplasia punctata 2 is caused by mutations in the EBP gene. This gene provides instructions for making an enzyme called 3-hydroxysteroid-8,7-isomerase, which is responsible for one of the final steps in the production of cholesterol. 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). Although too much cholesterol is a risk factor for heart disease, this molecule is necessary for normal embryonic development and has important functions both before and after birth. It is a structural component of cell membranes and plays a role in the production of certain hormones and digestive acids. Mutations in the EBP gene reduce the activity of 3-hydroxysteroid-8,7-isomerase, preventing cells from producing enough cholesterol. A shortage of this enzyme also allows potentially toxic byproducts of cholesterol production to build up in the body. The combination of low cholesterol levels and an accumulation of other substances likely disrupts the growth and development of many body systems. It is not known, however, how this disturbance in cholesterol production leads to the specific features of X-linked chondrodysplasia punctata 2. | X-linked chondrodysplasia punctata 2 |
Is X-linked chondrodysplasia punctata 2 inherited ? | This condition is inherited in an X-linked dominant pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In females (who have two X chromosomes), a mutation in one of the two copies of the EBP gene in each cell is sufficient to cause the disorder. Some cells produce a normal amount of 3-hydroxysteroid-8,7-isomerase and other cells produce none. The resulting overall reduction in the amount of this enzyme underlies the signs and symptoms of X-linked chondrodysplasia punctata 2. In males (who have only one X chromosome), a mutation in the EBP gene can result in a total loss of 3-hydroxysteroid-8,7-isomerase. A complete lack of this enzyme is usually lethal in the early stages of development, so few males have been born with X-linked chondrodysplasia punctata 2. | X-linked chondrodysplasia punctata 2 |
What are the treatments for X-linked chondrodysplasia punctata 2 ? | These resources address the diagnosis or management of X-linked chondrodysplasia punctata 2: - Gene Review: Gene Review: Chondrodysplasia Punctata 2, X-Linked - Genetic Testing Registry: Chondrodysplasia punctata 2 X-linked dominant 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 chondrodysplasia punctata 2 |
What is (are) fragile X-associated primary ovarian insufficiency ? | Fragile X-associated primary ovarian insufficiency (FXPOI) is a condition that affects women and is characterized by reduced function of the ovaries. The ovaries are the female reproductive organs in which egg cells are produced. As a form of primary ovarian insufficiency, FXPOI can cause irregular menstrual cycles, early menopause, an inability to have children (infertility), and elevated levels of a hormone known as follicle stimulating hormone (FSH). FSH is produced in both males and females and helps regulate the development of reproductive cells (eggs in females and sperm in males). In females, the level of FSH rises and falls, but overall it increases as a woman ages. In younger women, elevated levels may indicate early menopause and fertility problems. The severity of FXPOI is variable. The most severely affected women have overt POI (formerly called premature ovarian failure). These women have irregular or absent menstrual periods and elevated FSH levels before age 40. Overt POI often causes infertility. Other women have occult POI; they have normal menstrual periods but reduced fertility, and they may have elevated levels of FSH (in which case, it is called biochemical POI). The reduction in ovarian function caused by FXPOI results in low levels of the hormone estrogen, which leads to many of the common signs and symptoms of menopause, such as hot flashes, insomnia, and thinning of the bones (osteoporosis). Women with FXPOI undergo menopause an average of 5 years earlier than women without the condition. | fragile X-associated primary ovarian insufficiency |
How many people are affected by fragile X-associated primary ovarian insufficiency ? | An estimated 1 in 200 females has the genetic change that leads to FXPOI, although only about a quarter of them develop the condition. FXPOI accounts for about 4 to 6 percent of all cases of primary ovarian insufficiency in women. | fragile X-associated primary ovarian insufficiency |
What are the genetic changes related to fragile X-associated primary ovarian insufficiency ? | Mutations in the FMR1 gene increase a woman's risk of developing FXPOI. The FMR1 gene provides instructions for making a protein called FMRP, which helps regulate the production of other proteins. This protein plays a role in the functioning of nerve cells. It is also important for normal ovarian function, although the role is not fully understood. Women with FXPOI have a mutation in which a DNA segment, known as a CGG triplet repeat, is expanded within the FMR1 gene. Normally, this DNA segment is repeated from 5 to about 40 times. In women with FXPOI, however, the CGG segment is repeated 55 to 200 times. This mutation is known as an FMR1 gene premutation. Some studies show that women with about 44 to 54 CGG repeats, known as an intermediate (or gray zone) mutation, can also have features of FXPOI. An expansion of more than 200 repeats, a full mutation, causes a more serious disorder called fragile X syndrome, which is characterized by intellectual disability, learning problems, and certain physical features. For unknown reasons, the premutation leads to the overproduction of abnormal FMR1 mRNA that contains the expanded repeat region. The FMR1 mRNA is the genetic blueprint for FMRP. Researchers believe that the high levels of mRNA cause the signs and symptoms of FXPOI. It is thought that the mRNA attaches to other proteins and keeps them from performing their functions. In addition, the repeats make producing FMRP from the blueprint more difficult, and as a result, people with the FMR1 gene premutation can have less FMRP than normal. A reduction of this protein is not thought to be involved in FXPOI. However, it may cause mild versions of the features seen in fragile X syndrome, such as prominent ears, anxiety, and mood swings. | fragile X-associated primary ovarian insufficiency |
Is fragile X-associated primary ovarian insufficiency inherited ? | An increased risk of developing FXPOI is inherited in an X-linked dominant pattern. The FMR1 gene is located on the X chromosome, which is one of the two sex chromosomes. (The Y chromosome is the other sex chromosome.) The inheritance is dominant because one copy of the altered gene in each cell is sufficient to elevate the risk of developing FXPOI. In females (who have two X chromosomes), a mutation in one of the two copies of a gene in each cell can lead to the disorder. However, not all women who inherit an FMR1 premutation will develop FXPOI. Because males do not have ovaries, they are unaffected. | fragile X-associated primary ovarian insufficiency |
What are the treatments for fragile X-associated primary ovarian insufficiency ? | These resources address the diagnosis or management of FXPOI: - Gene Review: Gene Review: FMR1-Related Disorders - Genetic Testing Registry: Premature ovarian failure 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 | fragile X-associated primary ovarian insufficiency |
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