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What are the genetic changes related to galactosialidosis ?

Mutations in the CTSA gene cause all forms of galactosialidosis. The CTSA gene provides instructions for making a protein called cathepsin A, which is active in cellular compartments called lysosomes. These compartments contain enzymes that digest and recycle materials when they are no longer needed. Cathepsin A works together with two enzymes, neuraminidase 1 and beta-galactosidase, to form a protein complex. This complex breaks down sugar molecules (oligosaccharides) attached to certain proteins (glycoproteins) or fats (glycolipids). Cathepsin A is also found on the cell surface, where it forms a complex with neuraminidase 1 and a protein called elastin binding protein. Elastin binding protein plays a role in the formation of elastic fibers, a component of the connective tissues that form the body's supportive framework. CTSA mutations interfere with the normal function of cathepsin A. Most mutations disrupt the protein structure of cathepsin A, impairing its ability to form complexes with neuraminidase 1, beta-galactosidase, and elastin binding protein. As a result, these other enzymes are not functional, or they break down prematurely. Galactosialidosis belongs to a large family of lysosomal storage disorders, each caused by the deficiency of a specific lysosomal enzyme or protein. In galactosialidosis, impaired functioning of cathepsin A and other enzymes causes certain substances to accumulate in the lysosomes.

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Is galactosialidosis 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.

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What are the treatments for galactosialidosis ?

These resources address the diagnosis or management of galactosialidosis: - Genetic Testing Registry: Combined deficiency of sialidase AND beta galactosidase - MedlinePlus Encyclopedia: Hepatosplenomegaly (image) - MedlinePlus Encyclopedia: Hydrops fetalis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care

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What is (are) RAPADILINO syndrome ?

RAPADILINO syndrome is a rare condition that involves many parts of the body. Bone development is especially affected, causing many of the characteristic features of the condition. Most affected individuals have underdevelopment or absence of the bones in the forearms and the thumbs, which are known as radial ray malformations. The kneecaps (patellae) can also be underdeveloped or absent. Other features include an opening in the roof of the mouth (cleft palate) or a high arched palate; a long, slender nose; and dislocated joints. Many infants with RAPADILINO syndrome have difficulty feeding and experience diarrhea and vomiting. The combination of impaired bone development and feeding problems leads to slow growth and short stature in affected individuals. Some individuals with RAPADILINO syndrome have harmless light brown patches of skin that resemble a skin finding known as caf-au-lait spots. In addition, people with RAPADILINO syndrome have a slightly increased risk of developing a type of bone cancer known as osteosarcoma or a blood-related cancer called lymphoma. In individuals with RAPADILINO syndrome, osteosarcoma most often develops during childhood or adolescence, and lymphoma typically develops in young adulthood. The condition name is an acronym for the characteristic features of the disorder: RA for radial ray malformations, PA for patella and palate abnormalities, DI for diarrhea and dislocated joints, LI for limb abnormalities and little size, and NO for slender nose and normal intelligence. The varied signs and symptoms of RAPADILINO syndrome overlap with features of other disorders, namely Baller-Gerold syndrome and Rothmund-Thomson syndrome. These syndromes are also characterized by radial ray defects, skeletal abnormalities, and slow growth. All of these conditions can be caused by mutations in the same gene. Based on these similarities, researchers are investigating whether Baller-Gerold syndrome, Rothmund-Thomson syndrome, and RAPADILINO syndrome are separate disorders or part of a single syndrome with overlapping signs and symptoms.

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How many people are affected by RAPADILINO syndrome ?

RAPADILINO syndrome is a rare condition, although its worldwide prevalence is unknown. The condition was first identified in Finland, where it affects an estimated 1 in 75,000 individuals, although it has since been found in other regions.

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What are the genetic changes related to RAPADILINO syndrome ?

Mutations in the RECQL4 gene cause RAPADILINO syndrome. This gene provides instructions for making one member of a protein family called RecQ helicases. Helicases are enzymes that bind to DNA and temporarily unwind the two spiral strands (double helix) of the DNA molecule. This unwinding is necessary for copying (replicating) DNA in preparation for cell division and for repairing damaged DNA. The RECQL4 protein helps stabilize genetic information in the body's cells and plays a role in replicating and repairing DNA. The most common RECQL4 gene mutation involved in RAPADILINO syndrome causes the RECQL4 protein to be pieced together incorrectly. This genetic change results in the production of a protein that is missing a region called exon 7 and is unable to act as a helicase. The loss of helicase function may prevent normal DNA replication and repair, causing widespread damage to a person's genetic information over time. These changes may result in the accumulation of DNA errors and cell death, although it is unclear exactly how RECQL4 gene mutations lead to the specific features of RAPADILINO syndrome.

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Is RAPADILINO 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.

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What are the treatments for RAPADILINO syndrome ?

These resources address the diagnosis or management of RAPADILINO syndrome: - Genetic Testing Registry: Rapadilino 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

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What is (are) 22q13.3 deletion syndrome ?

22q13.3 deletion syndrome, which is also commonly known as Phelan-McDermid syndrome, is a disorder caused by the loss of a small piece of chromosome 22. The deletion occurs near the end of the chromosome at a location designated q13.3. The features of 22q13.3 deletion syndrome vary widely and involve many parts of the body. Characteristic signs and symptoms include developmental delay, moderate to profound intellectual disability, decreased muscle tone (hypotonia), and absent or delayed speech. Some people with this condition have autism or autistic-like behavior that affects communication and social interaction, such as poor eye contact, sensitivity to touch, and aggressive behaviors. They may also chew on non-food items such as clothing. Less frequently, people with this condition have seizures. Individuals with 22q13.3 deletion syndrome tend to have a decreased sensitivity to pain. Many also have a reduced ability to sweat, which can lead to a greater risk of overheating and dehydration. Some people with this condition have episodes of frequent vomiting and nausea (cyclic vomiting) and backflow of stomach acids into the esophagus (gastroesophageal reflux). People with 22q13.3 deletion syndrome typically have distinctive facial features, including a long, narrow head; prominent ears; a pointed chin; droopy eyelids (ptosis); and deep-set eyes. Other physical features seen with this condition include large and fleshy hands and/or feet, a fusion of the second and third toes (syndactyly), and small or abnormal toenails. Some affected individuals have rapid (accelerated) growth.

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How many people are affected by 22q13.3 deletion syndrome ?

At least 500 cases of 22q13.3 deletion syndrome are known.

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What are the genetic changes related to 22q13.3 deletion syndrome ?

22q13.3 deletion syndrome is caused by a deletion near the end of the long (q) arm of chromosome 22. The signs and symptoms of 22q13.3 deletion syndrome are probably related to the loss of multiple genes in this region. The size of the deletion varies among affected individuals. A ring chromosome 22 can also cause 22q13.3 deletion syndrome. A ring chromosome is a circular structure that occurs when a chromosome breaks in two places, the tips of the chromosome are lost, and the broken ends fuse together. People with ring chromosome 22 have one copy of this abnormal chromosome in some or all of their cells. Researchers believe that several critical genes near the end of the long (q) arm of chromosome 22 are lost when the ring chromosome 22 forms. If one of the chromosome break points is at position 22q13.3, people with ring chromosome 22 have similar signs and symptoms as those with a simple deletion. Researchers are working to identify all of the genes that contribute to the features of 22q13.3 deletion syndrome. They have determined that the loss of a particular gene on chromosome 22, SHANK3, is likely to be responsible for many of the syndrome's characteristic signs (such as developmental delay, intellectual disability, and impaired speech). Additional genes in the deleted region probably contribute to the varied features of 22q13.3 deletion syndrome.

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Is 22q13.3 deletion syndrome inherited ?

Most cases of 22q13.3 deletion syndrome are not inherited. 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 chromosome deletion to their children. When 22q13.3 deletion syndrome is inherited, its inheritance pattern is considered autosomal dominant because a deletion in one copy of chromosome 22 in each cell is sufficient to cause the condition. About 15 to 20 percent of people with 22q13.3 deletion syndrome inherit a chromosome abnormality from an unaffected parent. In these cases, the parent carries a chromosomal rearrangement called a balanced translocation, in which a segment from one chromosome has traded places with a segment from another chromosome, but no genetic material is gained or lost. Balanced translocations usually do not cause any health problems; however, they can become unbalanced as they are passed to the next generation. Children who inherit an unbalanced translocation can have a chromosomal rearrangement with extra or missing genetic material. Individuals with 22q13.3 deletion syndrome who inherit an unbalanced translocation are missing genetic material from the long arm of chromosome 22, which results in the health problems characteristic of this disorder.

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What are the treatments for 22q13.3 deletion syndrome ?

These resources address the diagnosis or management of 22q13.3 deletion syndrome: - Gene Review: Gene Review: Phelan-McDermid Syndrome - Genetic Testing Registry: 22q13.3 deletion syndrome - MedlinePlus Encyclopedia: Sweating--absent 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

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What is (are) spondylocostal dysostosis ?

Spondylocostal dysostosis is a group of conditions characterized by abnormal development of bones in the spine and ribs. The bones of the spine (vertebrae) are misshapen and abnormally joined together (fused). Many people with this condition have abnormal side-to-side curvature of the spine (scoliosis) due to malformation of the vertebrae. In addition to spine abnormalities, some of the rib bones may be fused together or missing. Affected individuals have short, rigid necks and short midsections because of the bone malformations. As a result, people with spondylocostal dysostosis have short bodies but normal length arms and legs, called short-trunk dwarfism. The spine and rib abnormalities cause other signs and symptoms of spondylocostal dysostosis. Infants with this condition are born with small chests that cannot expand adequately, often leading to life-threatening breathing problems. As the lungs expand in the narrow chest, the muscle that separates the abdomen from the chest cavity (the diaphragm) is forced down and the abdomen is pushed out. The increased pressure in the abdomen can cause a soft out-pouching around the lower abdomen (inguinal hernia), particularly in males with spondylocostal dysostosis. There are several types of spondylocostal dysostosis, designated types 1 through 4 and the autosomal dominant (AD) type. These types have similar features and are distinguished by their genetic cause and inheritance pattern. Spondylocostal dysostosis has often been grouped with a similar condition called spondylothoracic dysostosis, and both are called Jarcho-Levin syndrome; however, they are now considered distinct conditions.

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How many people are affected by spondylocostal dysostosis ?

Spondylocostal dysostosis is a rare condition, although its exact prevalence is unknown.

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What are the genetic changes related to spondylocostal dysostosis ?

Mutations in at least four genes are known to cause spondylocostal dysostosis: Mutations in the DLL3 gene cause spondylocostal dysostosis type 1; mutations in the MESP2 gene cause spondylocostal dysostosis type 2; mutations in the LFNG gene cause spondylocostal dysostosis type 3; and mutations in the HES7 gene cause spondylocostal dysostosis type 4. The genetic cause of AD spondylocostal dysostosis is unknown. The DLL3, MESP2, LFNG, and HES7 genes play a role in the Notch signaling pathway, an important pathway in embryonic development. One of the functions of the Notch pathway is separating future vertebrae from one another during early development, a process called somite segmentation. When this pathway is disrupted, somite segmentation does not occur properly, resulting in the malformation and fusion of the bones of the spine and ribs seen in spondylocostal dysostosis. Mutations in the four identified genes account for approximately 25 percent of diagnosed spondylocostal dysostosis. Researchers suggest that additional genes in the Notch signaling pathway might also be involved.

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Is spondylocostal dysostosis inherited ?

Spondylocostal dysostosis can have different inheritance patterns. Types 1, 2, 3, and 4 are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. AD spondylocostal dysostosis is inherited in an autosomal dominant pattern. Autosomal dominant inheritance means that one copy of an altered gene in each cell is sufficient to cause the disorder, although in these cases no causative genes have been identified. The signs and symptoms of spondylocostal dysostosis are typically more severe with autosomal recessive inheritance.

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What are the treatments for spondylocostal dysostosis ?

These resources address the diagnosis or management of spondylocostal dysostosis: - Gene Review: Gene Review: Spondylocostal Dysostosis, Autosomal Recessive - Genetic Testing Registry: Jarcho-Levin syndrome - Genetic Testing Registry: Spondylocostal dysostosis 1 - Genetic Testing Registry: Spondylocostal dysostosis 2 - Genetic Testing Registry: Spondylocostal dysostosis 3 - Genetic Testing Registry: Spondylocostal dysostosis 4, autosomal recessive - KidsHealth: X-Ray Exam (Scoliosis) - MedlinePlus Encyclopedia: Scoliosis These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care

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What is (are) Hashimoto thyroiditis ?

Hashimoto thyroiditis is a condition that affects the function of the thyroid, which is a butterfly-shaped gland in the lower neck. The thyroid makes hormones that help regulate a wide variety of critical body functions. For example, thyroid hormones influence growth and development, body temperature, heart rate, menstrual cycles, and weight. Hashimoto thyroiditis is a form of chronic inflammation that can damage the thyroid, reducing its ability to produce hormones. One of the first signs of Hashimoto thyroiditis is an enlargement of the thyroid called a goiter. Depending on its size, the enlarged thyroid can cause the neck to look swollen and may interfere with breathing and swallowing. As damage to the thyroid continues, the gland can shrink over a period of years and the goiter may eventually disappear. Other signs and symptoms resulting from an underactive thyroid can include excessive tiredness (fatigue), weight gain or difficulty losing weight, hair that is thin and dry, a slow heart rate, joint or muscle pain, and constipation. People with this condition may also have a pale, puffy face and feel cold even when others around them are warm. Affected women can have heavy or irregular menstrual periods and difficulty conceiving a child (impaired fertility). Difficulty concentrating and depression can also be signs of a shortage of thyroid hormones. Hashimoto thyroiditis usually appears in mid-adulthood, although it can occur earlier or later in life. Its signs and symptoms tend to develop gradually over months or years.

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How many people are affected by Hashimoto thyroiditis ?

Hashimoto thyroiditis affects 1 to 2 percent of people in the United States. It occurs more often in women than in men, which may be related to hormonal factors. The condition is the most common cause of thyroid underactivity (hypothyroidism) in the United States.

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What are the genetic changes related to Hashimoto thyroiditis ?

Hashimoto thyroiditis is thought to result from a combination of genetic and environmental factors. Some of these factors have been identified, but many remain unknown. Hashimoto thyroiditis is classified as an autoimmune disorder, one of a large group of conditions that occur when the immune system attacks the body's own tissues and organs. In people with Hashimoto thyroiditis, white blood cells called lymphocytes accumulate abnormally in the thyroid, which can damage it. The lymphocytes make immune system proteins called antibodies that attack and destroy thyroid cells. When too many thyroid cells become damaged or die, the thyroid can no longer make enough hormones to regulate body functions. This shortage of thyroid hormones underlies the signs and symptoms of Hashimoto thyroiditis. However, some people with thyroid antibodies never develop hypothyroidism or experience any related signs or symptoms. People with Hashimoto thyroiditis have an increased risk of developing other autoimmune disorders, including vitiligo, rheumatoid arthritis, Addison disease, type 1 diabetes, multiple sclerosis, and pernicious anemia. Variations in several genes have been studied as possible risk factors for Hashimoto thyroiditis. Some of these genes are part of a family called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders (such as viruses and bacteria). Other genes that have been associated with Hashimoto thyroiditis help regulate the immune system or are involved in normal thyroid function. Most of the genetic variations that have been discovered are thought to have a small impact on a person's overall risk of developing this condition. Other, nongenetic factors also play a role in Hashimoto thyroiditis. These factors may trigger the condition in people who are at risk, although the mechanism is unclear. Potential triggers include changes in sex hormones (particularly in women), viral infections, certain medications, exposure to ionizing radiation, and excess consumption of iodine (a substance involved in thyroid hormone production).

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Is Hashimoto thyroiditis inherited ?

The inheritance pattern of Hashimoto thyroiditis is unclear because many genetic and environmental factors appear to be involved. However, the condition can cluster in families, and having a close relative with Hashimoto thyroiditis or another autoimmune disorder likely increases a person's risk of developing the condition.

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What are the treatments for Hashimoto thyroiditis ?

These resources address the diagnosis or management of Hashimoto thyroiditis: - American Thyroid Association: Thyroid Function Tests - Genetic Testing Registry: Hashimoto thyroiditis - National Institute of Diabetes and Digestive and Kidney Diseases: Thyroid Function Tests 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

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What is (are) Alport syndrome ?

Alport syndrome is a genetic condition characterized by kidney disease, hearing loss, and eye abnormalities. People with Alport syndrome experience progressive loss of kidney function. Almost all affected individuals have blood in their urine (hematuria), which indicates abnormal functioning of the kidneys. Many people with Alport syndrome also develop high levels of protein in their urine (proteinuria). The kidneys become less able to function as this condition progresses, resulting in end-stage renal disease (ESRD). People with Alport syndrome frequently develop sensorineural hearing loss, which is caused by abnormalities of the inner ear, during late childhood or early adolescence. Affected individuals may also have misshapen lenses in the eyes (anterior lenticonus) and abnormal coloration of the light-sensitive tissue at the back of the eye (retina). These eye abnormalities seldom lead to vision loss. Significant hearing loss, eye abnormalities, and progressive kidney disease are more common in males with Alport syndrome than in affected females.

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How many people are affected by Alport syndrome ?

Alport syndrome occurs in approximately 1 in 50,000 newborns.

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What are the genetic changes related to Alport syndrome ?

Mutations in the COL4A3, COL4A4, and COL4A5 genes cause Alport syndrome. These genes each provide instructions for making one component of a protein called type IV collagen. This protein plays an important role in the kidneys, specifically in structures called glomeruli. Glomeruli are clusters of specialized blood vessels that remove water and waste products from blood and create urine. Mutations in these genes result in abnormalities of the type IV collagen in glomeruli, which prevents the kidneys from properly filtering the blood and allows blood and protein to pass into the urine. Gradual scarring of the kidneys occurs, eventually leading to kidney failure in many people with Alport syndrome. Type IV collagen is also an important component of inner ear structures, particularly the organ of Corti, that transform sound waves into nerve impulses for the brain. Alterations in type IV collagen often result in abnormal inner ear function, which can lead to hearing loss. In the eye, this protein is important for maintaining the shape of the lens and the normal color of the retina. Mutations that disrupt type IV collagen can result in misshapen lenses and an abnormally colored retina.

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Is Alport syndrome inherited ?

Alport syndrome can have different inheritance patterns. About 80 percent of cases are caused by mutations in the COL4A5 gene and are inherited in an X-linked pattern. This 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 COL4A5 gene in each cell is sufficient to cause kidney failure and other severe symptoms of the disorder. In females (who have two X chromosomes), a mutation in one copy of the COL4A5 gene usually only results in hematuria, but some women experience more severe symptoms. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In approximately 15 percent of cases, Alport syndrome results from mutations in both copies of the COL4A3 or COL4A4 gene and is inherited in an autosomal recessive pattern. The parents of an individual with the autosomal recessive form of this condition each have one copy of the mutated gene and are called carriers. Some carriers are unaffected and others develop a less severe condition called thin basement membrane nephropathy, which is characterized by hematuria. Alport syndrome has autosomal dominant inheritance in about 5 percent of cases. People with this form of Alport syndrome have one mutation in either the COL4A3 or COL4A4 gene in each cell. It remains unclear why some individuals with one mutation in the COL4A3 or COL4A4 gene have autosomal dominant Alport syndrome and others have thin basement membrane nephropathy.

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What are the treatments for Alport syndrome ?

These resources address the diagnosis or management of Alport syndrome: - Gene Review: Gene Review: Alport Syndrome and Thin Basement Membrane Nephropathy - Genetic Testing Registry: Alport syndrome - Genetic Testing Registry: Alport syndrome, X-linked recessive - Genetic Testing Registry: Alport syndrome, autosomal dominant - Genetic Testing Registry: Alport syndrome, autosomal recessive - MedlinePlus Encyclopedia: Alport Syndrome - MedlinePlus Encyclopedia: End-Stage Kidney 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

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What is (are) cerebral cavernous malformation ?

Cerebral cavernous malformations are collections of small blood vessels (capillaries) in the brain that are enlarged and irregular in structure. These capillaries have abnormally thin walls, and they lack other support tissues, such as elastic fibers, which normally make them stretchy. As a result, the blood vessels are prone to leakage, which can cause the health problems related to this condition. Cavernous malformations can occur anywhere in the body, but usually produce serious signs and symptoms only when they occur in the brain and spinal cord (which are described as cerebral). Approximately 25 percent of individuals with cerebral cavernous malformations never experience any related health problems. Other people with this condition may experience serious signs and symptoms such as headaches, seizures, paralysis, hearing or vision loss, and bleeding in the brain (cerebral hemorrhage). Severe brain hemorrhages can result in death. The location and number of cerebral cavernous malformations determine the severity of this disorder. These malformations can change in size and number over time. There are two forms of the condition: familial and sporadic. The familial form is passed from parent to child, and affected individuals typically have multiple cerebral cavernous malformations. The sporadic form occurs in people with no family history of the disorder. These individuals typically have only one malformation.

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How many people are affected by cerebral cavernous malformation ?

Cerebral cavernous malformations affect about 0.5 percent of the population worldwide.

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What are the genetic changes related to cerebral cavernous malformation ?

Mutations in at least three genes, KRIT1 (also known as CCM1), CCM2, and PDCD10 (also known as CCM3), cause familial cerebral cavernous malformations. The precise functions of these genes are not fully understood. Studies show that the proteins produced from these genes are found in the junctions connecting neighboring blood vessel cells. The proteins interact with each other as part of a complex that strengthens the interactions between cells and limits leakage from the blood vessels. Mutations in any of the three genes impair the function of the protein complex, resulting in weakened cell-to-cell junctions and increased leakage from vessels as seen in cerebral cavernous malformations. Mutations in these three genes account for 85 to 95 percent of all cases of familial cerebral cavernous malformations. The remaining 5 to 15 percent of cases may be due to mutations in unidentified genes or to other unknown causes. Mutations in the KRIT1, CCM2, and PDCD10 genes are not involved in sporadic cerebral cavernous malformations. The cause of this form of the condition is unknown.

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Is cerebral cavernous malformation inherited ?

This condition has an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In the familial form, an affected person inherits the mutation from one affected parent. Most people with cerebral cavernous malformations have the sporadic form of the disorder. These cases occur in people with no history of the disorder in their family.

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What are the treatments for cerebral cavernous malformation ?

These resources address the diagnosis or management of cerebral cavernous malformation: - Angioma Alliance: Imaging and Diagnostics - Gene Review: Gene Review: Familial Cerebral Cavernous Malformation - Genetic Testing Registry: Cerebral cavernous malformation - Genetic Testing Registry: Cerebral cavernous malformations 1 - Genetic Testing Registry: Cerebral cavernous malformations 2 - Genetic Testing Registry: Cerebral cavernous malformations 3 - MedlinePlus Encyclopedia: Cerebral angiography 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

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What is (are) Turner syndrome ?

Turner syndrome is a chromosomal condition that affects development in females. The most common feature of Turner syndrome is short stature, which becomes evident by about age 5. An early loss of ovarian function (ovarian hypofunction or premature ovarian failure) is also very common. The ovaries develop normally at first, but egg cells (oocytes) usually die prematurely and most ovarian tissue degenerates before birth. Many affected girls do not undergo puberty unless they receive hormone therapy, and most are unable to conceive (infertile). A small percentage of females with Turner syndrome retain normal ovarian function through young adulthood. About 30 percent of females with Turner syndrome have extra folds of skin on the neck (webbed neck), a low hairline at the back of the neck, puffiness or swelling (lymphedema) of the hands and feet, skeletal abnormalities, or kidney problems. One third to one half of individuals with Turner syndrome are born with a heart defect, such as a narrowing of the large artery leaving the heart (coarctation of the aorta) or abnormalities of the valve that connects the aorta with the heart (the aortic valve). Complications associated with these heart defects can be life-threatening. Most girls and women with Turner syndrome have normal intelligence. Developmental delays, nonverbal learning disabilities, and behavioral problems are possible, although these characteristics vary among affected individuals.

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How many people are affected by Turner syndrome ?

This condition occurs in about 1 in 2,500 newborn girls worldwide, but it is much more common among pregnancies that do not survive to term (miscarriages and stillbirths).

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What are the genetic changes related to Turner syndrome ?

Turner syndrome is related to the X chromosome, which is one of the two sex chromosomes. People typically have two sex chromosomes in each cell: females have two X chromosomes, while males have one X chromosome and one Y chromosome. Turner syndrome results when one normal X chromosome is present in a female's cells and the other sex chromosome is missing or structurally altered. The missing genetic material affects development before and after birth. About half of individuals with Turner syndrome have monosomy X, which means each cell in the individual's body has only one copy of the X chromosome instead of the usual two sex chromosomes. Turner syndrome can also occur if one of the sex chromosomes is partially missing or rearranged rather than completely absent. Some women with Turner syndrome have a chromosomal change in only some of their cells, which is known as mosaicism. Women with Turner syndrome caused by X chromosome mosaicism are said to have mosaic Turner syndrome. Researchers have not determined which genes on the X chromosome are associated with most of the features of Turner syndrome. They have, however, identified one gene called SHOX that is important for bone development and growth. The loss of one copy of this gene likely causes short stature and skeletal abnormalities in women with Turner syndrome.

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Is Turner syndrome inherited ?

Most cases of Turner syndrome are not inherited. When this condition results from monosomy X, the chromosomal abnormality occurs as a random event during the formation of reproductive cells (eggs and sperm) in the affected person's parent. An error in cell division called nondisjunction can result in reproductive cells with an abnormal number of chromosomes. For example, an egg or sperm cell may lose a sex chromosome as a result of nondisjunction. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have a single X chromosome in each cell and will be missing the other sex chromosome. Mosaic Turner syndrome is also not inherited. In an affected individual, it occurs as a random event during cell division in early fetal development. As a result, some of an affected person's cells have the usual two sex chromosomes, and other cells have only one copy of the X chromosome. Other sex chromosome abnormalities are also possible in females with X chromosome mosaicism. Rarely, Turner syndrome caused by a partial deletion of the X chromosome can be passed from one generation to the next.

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What are the treatments for Turner syndrome ?

These resources address the diagnosis or management of Turner syndrome: - Genetic Testing Registry: Turner syndrome - MedlinePlus Encyclopedia: Ovarian Hypofunction - MedlinePlus Encyclopedia: Turner 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

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What is (are) autosomal dominant congenital stationary night blindness ?

Autosomal dominant congenital stationary night blindness is a disorder of the retina, which is the specialized tissue at the back of the eye that detects light and color. People with this condition typically have difficulty seeing and distinguishing objects in low light (night blindness). For example, they are not able to identify road signs at night and some people cannot see stars in the night sky. Affected individuals have normal daytime vision and typically do not have other vision problems related to this disorder. The night blindness associated with this condition is congenital, which means it is present from birth. This vision impairment tends to remain stable (stationary); it does not worsen over time.

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How many people are affected by autosomal dominant congenital stationary night blindness ?

Autosomal dominant congenital stationary night blindness is likely a rare disease; however, its prevalence is unknown.

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What are the genetic changes related to autosomal dominant congenital stationary night blindness ?

Mutations in the RHO, GNAT1, or PDE6B gene cause autosomal dominant congenital stationary night blindness. The proteins produced from these genes are necessary for normal vision, particularly in low-light conditions. These proteins are found in specialized light receptor cells in the retina called rods. Rods transmit visual signals from the eye to the brain when light is dim. The RHO gene provides instructions for making a protein called rhodopsin, which is turned on (activated) by light entering the eye. Rhodopsin then attaches (binds) to and activates the protein produced from the GNAT1 gene, alpha ()-transducin. The -transducin protein then triggers the activation of a protein called cGMP-PDE, which is made up of multiple parts (subunits) including a subunit produced from the PDE6B gene. Activated cGMP-PDE triggers a series of chemical reactions that create electrical signals. These signals are transmitted from rod cells to the brain, where they are interpreted as vision. Mutations in the RHO, GNAT1, or PDE6B gene disrupt the normal signaling that occurs within rod cells. As a result, the rods cannot effectively transmit signals to the brain, leading to a lack of visual perception in low light.

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Is autosomal dominant congenital stationary night blindness 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.

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What are the treatments for autosomal dominant congenital stationary night blindness ?

These resources address the diagnosis or management of autosomal dominant congenital stationary night blindness: - Genetic Testing Registry: Congenital stationary night blindness 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

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What is (are) Renpenning syndrome ?

Renpenning syndrome is a disorder that almost exclusively affects males, causing developmental delay, moderate to severe intellectual disability, and distinctive physical features. Individuals with Renpenning syndrome typically have short stature and a small head size (microcephaly). Facial features characteristic of this disorder include a long, narrow face; outside corners of the eyes that point upward (upslanting palpebral fissures); a long, bulbous nose with a low-hanging separation between the nostrils (overhanging columella); a shortened space between the nose and mouth (philtrum); and cup-shaped ears. Males with Renpenning syndrome generally have small testes. Seizures and wasting away (atrophy) of muscles used for movement (skeletal muscles) may also occur in this disorder. About 20 percent of individuals with Renpenning syndrome also have other features, which may include a gap or split in structures that make up the eye (coloboma), an opening in the roof of the mouth (cleft palate), heart abnormalities, or malformations of the anus. Certain combinations of the features that often occur in Renpenning syndrome are sometimes called by other names, such as Golabi-Ito-Hall syndrome or Sutherland-Haan syndrome. However, all these syndromes, which have the same genetic cause, are now generally grouped under the term Renpenning syndrome.

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How many people are affected by Renpenning syndrome ?

Renpenning syndrome is a rare disorder; its prevalence is unknown. More than 60 affected individuals in at least 15 families have been identified.

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What are the genetic changes related to Renpenning syndrome ?

Renpenning syndrome is caused by mutations in the PQBP1 gene. This gene provides instructions for making a protein called polyglutamine-binding protein 1. This protein attaches (binds) to stretches of multiple copies of a protein building block (amino acid) called glutamine in certain other proteins. While the specific function of polyglutamine-binding protein 1 is not well understood, it is believed to play a role in processing and transporting RNA, a chemical cousin of DNA that serves as the genetic blueprint for the production of proteins. In nerve cells (neurons) such as those in the brain, polyglutamine-binding protein 1 is found in structures called RNA granules. These granules allow the transport and storage of RNA within the cell. The RNA is held within the granules until the genetic information it carries is translated to produce proteins or until cellular signals or environmental factors trigger the RNA to be degraded. Through these mechanisms, polyglutamine-binding protein 1 is thought to help control the way genetic information is used (gene expression) in neurons. This control is important for normal brain development. Most of the mutations in the PQBP1 gene that cause Renpenning syndrome result in an abnormally short polyglutamine-binding protein 1. The function of a shortened or otherwise abnormal protein is likely impaired and interferes with normal gene expression in neurons, resulting in abnormal development of the brain and the signs and symptoms of Renpenning syndrome.

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Is Renpenning syndrome inherited ?

This condition is inherited in an X-linked recessive pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation typically has 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.

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What are the treatments for Renpenning syndrome ?

These resources address the diagnosis or management of Renpenning syndrome: - Genetic Testing Registry: Renpenning syndrome 1 - Greenwood Genetics Center: X-Linked Intellectual Disability - Kennedy Krieger Institute: Center for Genetic Disorders of Cognition and Behavior 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

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What is (are) multiple epiphyseal dysplasia ?

Multiple epiphyseal dysplasia is a disorder of cartilage and bone development primarily affecting the ends of the long bones in the arms and legs (epiphyses). There are two types of multiple epiphyseal dysplasia, which can be distinguished by their pattern of inheritance. Both the dominant and recessive types have relatively mild signs and symptoms, including joint pain that most commonly affects the hips and knees, early-onset arthritis, and a waddling walk. Although some people with multiple epiphyseal dysplasia have mild short stature as adults, most are of normal height. The majority of individuals are diagnosed during childhood; however, some mild cases may not be diagnosed until adulthood. Recessive multiple epiphyseal dysplasia is distinguished from the dominant type by malformations of the hands, feet, and knees and abnormal curvature of the spine (scoliosis). About 50 percent of individuals with recessive multiple epiphyseal dysplasia are born with at least one abnormal feature, including an inward- and upward-turning foot (clubfoot), an opening in the roof of the mouth (cleft palate), an unusual curving of the fingers or toes (clinodactyly), or ear swelling. An abnormality of the kneecap called a double-layered patella is also relatively common.

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How many people are affected by multiple epiphyseal dysplasia ?

The incidence of dominant multiple epiphyseal dysplasia is estimated to be at least 1 in 10,000 newborns. The incidence of recessive multiple epiphyseal dysplasia is unknown. Both forms of this disorder may actually be more common because some people with mild symptoms are never diagnosed.

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What are the genetic changes related to multiple epiphyseal dysplasia ?

Mutations in the COMP, COL9A1, COL9A2, COL9A3, or MATN3 gene can cause dominant multiple epiphyseal dysplasia. These genes provide instructions for making proteins that are found in the spaces between cartilage-forming cells (chondrocytes). These proteins interact with each other and play an important role in cartilage and bone formation. Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone, except for the cartilage that continues to cover and protect the ends of bones and is present in the nose and external ears. The majority of individuals with dominant multiple epiphyseal dysplasia have mutations in the COMP gene. About 10 percent of affected individuals have mutations in the MATN3 gene. Mutations in the COMP or MATN3 gene prevent the release of the proteins produced from these genes into the spaces between the chondrocytes. The absence of these proteins leads to the formation of abnormal cartilage, which can cause the skeletal problems characteristic of dominant multiple epiphyseal dysplasia. The COL9A1, COL9A2, and COL9A3 genes provide instructions for making a protein called type IX collagen. Collagens are a family of proteins that strengthen and support connective tissues, such as skin, bone, cartilage, tendons, and ligaments. Mutations in the COL9A1, COL9A2, or COL9A3 gene are found in less than five percent of individuals with dominant multiple epiphyseal dysplasia. It is not known how mutations in these genes cause the signs and symptoms of this disorder. Research suggests that mutations in these genes may cause type IX collagen to accumulate inside the cell or interact abnormally with other cartilage components. Some people with dominant multiple epiphyseal dysplasia do not have a mutation in the COMP, COL9A1, COL9A2, COL9A3, or MATN3 gene. In these cases, the cause of the condition is unknown. Mutations in the SLC26A2 gene cause recessive multiple epiphyseal dysplasia. This gene provides instructions for making a protein that is essential for the normal development of cartilage and for its conversion to bone. Mutations in the SLC26A2 gene alter the structure of developing cartilage, preventing bones from forming properly and resulting in the skeletal problems characteristic of recessive multiple epiphyseal dysplasia.

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Is multiple epiphyseal dysplasia inherited ?

Multiple epiphyseal dysplasia can have different inheritance patterns. This condition 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. In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family. Multiple epiphyseal dysplasia can also be inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition.

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What are the treatments for multiple epiphyseal dysplasia ?

These resources address the diagnosis or management of multiple epiphyseal dysplasia: - Cedars-Sinai Medical Center - Gene Review: Gene Review: Multiple Epiphyseal Dysplasia, Dominant - Gene Review: Gene Review: Multiple Epiphyseal Dysplasia, Recessive - Genetic Testing Registry: Multiple epiphyseal dysplasia 1 - Genetic Testing Registry: Multiple epiphyseal dysplasia 2 - Genetic Testing Registry: Multiple epiphyseal dysplasia 3 - Genetic Testing Registry: Multiple epiphyseal dysplasia 4 - Genetic Testing Registry: Multiple epiphyseal dysplasia 5 - Genetic Testing Registry: Multiple epiphyseal dysplasia 6 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

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What is (are) type A insulin resistance syndrome ?

Type A insulin resistance syndrome is a rare disorder characterized by severe insulin resistance, a condition in which the body's tissues and organs do not respond properly to the hormone insulin. Insulin normally helps regulate blood sugar levels by controlling how much sugar (in the form of glucose) is passed from the bloodstream into cells to be used as energy. In people with type A insulin resistance syndrome, insulin resistance impairs blood sugar regulation and ultimately leads to a condition called diabetes mellitus, in which blood sugar levels can become dangerously high. Severe insulin resistance also underlies the other signs and symptoms of type A insulin resistance syndrome. In affected females, the major features of the condition become apparent in adolescence. Many affected females do not begin menstruation by age 16 (primary amenorrhea) or their periods may be light and irregular (oligomenorrhea). They develop cysts on the ovaries and excessive body hair growth (hirsutism). Most affected females also develop a skin condition called acanthosis nigricans, in which the skin in body folds and creases becomes thick, dark, and velvety. Unlike most people with insulin resistance, females with type A insulin resistance syndrome are usually not overweight. The features of type A insulin resistance syndrome are more subtle in affected males. Some males have low blood sugar (hypoglycemia) as the only sign; others may also have acanthosis nigricans. In many cases, males with this condition come to medical attention only when they develop diabetes mellitus in adulthood. Type A insulin resistance syndrome is one of a group of related conditions described as inherited severe insulin resistance syndromes. These disorders, which also include Donohue syndrome and Rabson-Mendenhall syndrome, are considered part of a spectrum. Type A insulin resistance syndrome represents the mildest end of the spectrum: its features often do not become apparent until puberty or later, and it is generally not life-threatening.

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How many people are affected by type A insulin resistance syndrome ?

Type A insulin resistance syndrome is estimated to affect about 1 in 100,000 people worldwide. Because females have more health problems associated with the condition, it is diagnosed more often in females than in males.

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What are the genetic changes related to type A insulin resistance syndrome ?

Type A insulin resistance syndrome results from mutations in the INSR gene. This gene provides instructions for making a protein called an insulin receptor, which is found in many types of cells. Insulin receptors are embedded in the outer membrane surrounding the cell, where they attach (bind) to insulin circulating in the bloodstream. This binding triggers signaling pathways that influence many cell functions. Most of the INSR gene mutations that cause type A insulin resistance syndrome lead to the production of a faulty insulin receptor that cannot transmit signals properly. Although insulin is present in the bloodstream, the defective receptors make it less able to exert its effects on cells and tissues. This severe resistance to the effects of insulin impairs blood sugar regulation and leads to diabetes mellitus. In females with type A insulin resistance syndrome, excess insulin in the bloodstream interacts with hormonal factors during adolescence to cause abnormalities of the menstrual cycle, ovarian cysts, and other features of the disorder. This condition is designated as type A to distinguish it from type B insulin resistance syndrome. Although the two disorders have similar signs and symptoms, type B is not caused by INSR gene mutations; instead, it results from an abnormality of the immune system that blocks insulin receptor function.

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Is type A insulin resistance syndrome inherited ?

Type A insulin resistance syndrome can have either an autosomal dominant or, less commonly, an autosomal recessive pattern of inheritance. In autosomal dominant inheritance, 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. In autosomal recessive inheritance, both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

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What are the treatments for type A insulin resistance syndrome ?

These resources address the diagnosis or management of type A insulin resistance syndrome: - Genetic Testing Registry: Insulin-resistant diabetes mellitus AND acanthosis nigricans 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

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What is (are) Bartter syndrome ?

Bartter syndrome is a group of very similar kidney disorders that cause an imbalance of potassium, sodium, chloride, and related molecules in the body. In some cases, Bartter syndrome becomes apparent before birth. The disorder can cause polyhydramnios, which is an increased volume of fluid surrounding the fetus (amniotic fluid). Polyhydramnios increases the risk of premature birth. Beginning in infancy, affected individuals often fail to grow and gain weight at the expected rate (failure to thrive). They lose excess amounts of salt (sodium chloride) in their urine, which leads to dehydration, constipation, and increased urine production (polyuria). In addition, large amounts of calcium are lost through the urine (hypercalciuria), which can cause weakening of the bones (osteopenia). Some of the calcium is deposited in the kidneys as they are concentrating urine, leading to hardening of the kidney tissue (nephrocalcinosis). Bartter syndrome is also characterized by low levels of potassium in the blood (hypokalemia), which can result in muscle weakness, cramping, and fatigue. Rarely, affected children develop hearing loss caused by abnormalities in the inner ear (sensorineural deafness). Two major forms of Bartter syndrome are distinguished by their age of onset and severity. One form begins before birth (antenatal) and is often life-threatening. The other form, often called the classical form, begins in early childhood and tends to be less severe. Once the genetic causes of Bartter syndrome were identified, researchers also split the disorder into different types based on the genes involved. Types I, II, and IV have the features of antenatal Bartter syndrome. Because type IV is also associated with hearing loss, it is sometimes called antenatal Bartter syndrome with sensorineural deafness. Type III usually has the features of classical Bartter syndrome.

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How many people are affected by Bartter syndrome ?

The exact prevalence of this disorder is unknown, although it likely affects about 1 per million people worldwide. The condition appears to be more common in Costa Rica and Kuwait than in other populations.

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What are the genetic changes related to Bartter syndrome ?

Bartter syndrome can be caused by mutations in at least five genes. Mutations in the SLC12A1 gene cause type I. Type II results from mutations in the KCNJ1 gene. Mutations in the CLCNKB gene are responsible for type III. Type IV can result from mutations in the BSND gene or from a combination of mutations in the CLCNKA and CLCNKB genes. The genes associated with Bartter syndrome play important roles in normal kidney function. The proteins produced from these genes are involved in the kidneys' reabsorption of salt. Mutations in any of the five genes impair the kidneys' ability to reabsorb salt, leading to the loss of excess salt in the urine (salt wasting). Abnormalities of salt transport also affect the reabsorption of other charged atoms (ions), including potassium and calcium. The resulting imbalance of ions in the body leads to the major features of Bartter syndrome. In some people with Bartter syndrome, the genetic cause of the disorder is unknown. Researchers are searching for additional genes that may be associated with this condition.

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Is Bartter 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.

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What are the treatments for Bartter syndrome ?

These resources address the diagnosis or management of Bartter syndrome: - Genetic Testing Registry: Bartter syndrome antenatal type 1 - Genetic Testing Registry: Bartter syndrome antenatal type 2 - Genetic Testing Registry: Bartter syndrome type 3 - Genetic Testing Registry: Bartter syndrome type 4 - Genetic Testing Registry: Bartter syndrome, type 4b - Genetic Testing Registry: Bartter's syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care

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What is (are) mucopolysaccharidosis type VI ?

Mucopolysaccharidosis type VI (MPS VI), also known as Maroteaux-Lamy syndrome, is a progressive condition that causes many tissues and organs to enlarge and become inflamed or scarred. Skeletal abnormalities are also common in this condition. The rate at which symptoms worsen varies among affected individuals. People with MPS VI generally do not display any features of the condition at birth. They often begin to show signs and symptoms of MPS VI during early childhood. The features of MPS VI include a large head (macrocephaly), a buildup of fluid in the brain (hydrocephalus), distinctive-looking facial features that are described as "coarse," and a large tongue (macroglossia). Affected individuals also frequently develop heart valve abnormalities, an enlarged liver and spleen (hepatosplenomegaly), and a soft out-pouching around the belly-button (umbilical hernia) or lower abdomen (inguinal hernia). The airway may become narrow in some people with MPS VI, leading to frequent upper respiratory infections and short pauses in breathing during sleep (sleep apnea). The clear covering of the eye (cornea) typically becomes cloudy, which can cause significant vision loss. People with MPS VI may also have recurrent ear infections and hearing loss. Unlike other types of mucopolysaccharidosis, MPS VI does not affect intelligence. MPS VI causes various skeletal abnormalities, including short stature and joint deformities (contractures) that affect mobility. Individuals with this condition may also have dysostosis multiplex, which refers to multiple skeletal abnormalities seen on x-ray. Carpal tunnel syndrome develops in many children with MPS VI and is characterized by numbness, tingling, and weakness in the hands and fingers. People with MPS VI may develop a narrowing of the spinal canal (spinal stenosis) in the neck, which can compress and damage the spinal cord. The life expectancy of individuals with MPS VI depends on the severity of symptoms. Without treatment, severely affected individuals may survive only until late childhood or adolescence. Those with milder forms of the disorder usually live into adulthood, although their life expectancy may be reduced. Heart disease and airway obstruction are major causes of death in people with MPS VI.

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How many people are affected by mucopolysaccharidosis type VI ?

The exact incidence of MPS VI is unknown, although it is estimated to occur in 1 in 250,000 to 600,000 newborns.

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What are the genetic changes related to mucopolysaccharidosis type VI ?

Mutations in the ARSB gene cause MPS VI. The ARSB gene provides instructions for producing an enzyme called arylsulfatase B, which is involved in the breakdown of large sugar molecules called glycosaminoglycans (GAGs). GAGs were originally called mucopolysaccharides, which is where this condition gets its name. Mutations in the ARSB gene reduce or completely eliminate the function of arylsulfatase B. The lack of arylsulfatase B activity leads to the accumulation of GAGs within cells, specifically inside the lysosomes. Lysosomes are compartments in the cell that digest and recycle different types of molecules. Conditions such as MPS VI that cause molecules to build up inside the lysosomes are called lysosomal storage disorders. The accumulation of GAGs within lysosomes increases the size of the cells, which is why many tissues and organs are enlarged in this disorder. Researchers believe that the buildup of GAGs may also interfere with the functions of other proteins inside lysosomes, triggering inflammation and cell death.

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Is mucopolysaccharidosis 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.

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What are the treatments for mucopolysaccharidosis type VI ?

These resources address the diagnosis or management of mucopolysaccharidosis type VI: - Emory University Lysosomal Storage Disease Center - Genetic Testing Registry: Mucopolysaccharidosis type VI - MedlinePlus Encyclopedia: Mucopolysaccharides - National Institute of Neurological Disorders and Stroke: Mucopolysaccharidoses Fact Sheet - National MPS Society: Treatments 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

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What is (are) hereditary folate malabsorption ?

Hereditary folate malabsorption is a disorder that interferes with the body's ability to absorb certain B vitamins (called folates) from food. Folates are important for many cell functions, including the production of DNA and its chemical cousin, RNA. Infants with hereditary folate malabsorption are born with normal amounts of folates in their body because they obtain these vitamins from their mother's blood before birth. They generally begin to show signs and symptoms of the disorder within the first few months of life because their ability to absorb folates from food is impaired. Infants with hereditary folate malabsorption experience feeding difficulties, diarrhea, and failure to gain weight and grow at the expected rate (failure to thrive). Affected individuals usually develop a blood disorder called megaloblastic anemia. Megaloblastic anemia occurs when a person has a low number of red blood cells (anemia), and the remaining red blood cells are larger than normal (megaloblastic). The symptoms of this blood disorder may include decreased appetite, lack of energy, headaches, pale skin, and tingling or numbness in the hands and feet. People with hereditary folate malabsorption may also have a deficiency of white blood cells (leukopenia), leading to increased susceptibility to infections. In addition, they may have a reduction in the amount of platelets (thrombocytopenia), which can result in easy bruising and abnormal bleeding. Some infants with hereditary folate malabsorption exhibit neurological problems such as developmental delay and seizures. Over time, untreated individuals may develop intellectual disability and difficulty coordinating movements (ataxia).

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How many people are affected by hereditary folate malabsorption ?

The prevalence of hereditary folate malabsorption is unknown. Approximately 15 affected families have been reported worldwide. Researchers believe that some infants with this disorder may not get diagnosed or treated, particularly in areas where advanced medical care is not available.

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What are the genetic changes related to hereditary folate malabsorption ?

The SLC46A1 gene provides instructions for making a protein called the proton-coupled folate transporter (PCFT). PCFT is important for normal functioning of intestinal epithelial cells, which are cells that line the walls of the intestine. These cells have fingerlike projections called microvilli that absorb nutrients from food as it passes through the intestine. Based on their appearance, groups of these microvilli are known collectively as the brush border. PCFT is involved in the process of using energy to move folates across the brush border membrane, a mechanism called active transport. It is also involved in the transport of folates between the brain and the fluid that surrounds it (cerebrospinal fluid). Mutations in the SLC46A1 gene result in a PCFT protein that has little or no activity. In some cases the mutated protein is not transported to the cell membrane, and so it is unable to perform its function. A lack of functional PCFT impairs the body's ability to absorb folates from food, resulting in the signs and symptoms of hereditary folate malabsorption.

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Is hereditary folate malabsorption 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.

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What are the treatments for hereditary folate malabsorption ?

These resources address the diagnosis or management of hereditary folate malabsorption: - Gene Review: Gene Review: Hereditary Folate Malabsorption - Genetic Testing Registry: Congenital defect of folate absorption - MedlinePlus Encyclopedia: Folate - MedlinePlus Encyclopedia: Folate Deficiency - MedlinePlus Encyclopedia: Folate-Deficiency Anemia - MedlinePlus Encyclopedia: Malabsorption 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

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What is (are) dermatofibrosarcoma protuberans ?

Dermatofibrosarcoma protuberans is a rare type of cancer that causes a tumor in the deep layers of skin. This condition is a type of soft tissue sarcoma, which are cancers that affect skin, fat, muscle, and similar tissues. In dermatofibrosarcoma protuberans, the tumor most often starts as a small, firm patch of skin, usually 1 to 5 centimeters in diameter, that is usually purplish, reddish, or flesh-colored. The tumor typically grows slowly and can become a raised nodule. Occasionally, the tumor begins as a flat or depressed patch of skin (plaque). Tumors are most commonly found on the torso and can also be found on the arms, legs, head, or neck. Affected individuals usually first show signs of this condition in their thirties, but the age at which a tumor appears varies widely. In dermatofibrosarcoma protuberans, the tumor has a tendency to return after being removed. However, it does not often spread to other parts of the body (metastasize). There are several variants of dermatofibrosarcoma protuberans in which different cell types are involved in the tumor. Bednar tumors, often called pigmented dermatofibrosarcoma protuberans, contain dark-colored (pigmented) cells called melanin-containing dendritic cells. Myxoid dermatofibrosarcoma protuberans tumors contain an abnormal type of connective tissue known as myxoid stroma. Giant cell fibroblastoma, which is sometimes referred to as juvenile dermatofibrosarcoma protuberans because it typically affects children and adolescents, is characterized by giant cells in the tumor. Rarely, the tumors involved in the different types of dermatofibrosarcoma protuberans can have regions that look similar to fibrosarcoma, a more aggressive type of soft tissue sarcoma. In these cases, the condition is called fibrosarcomatous dermatofibrosarcoma protuberans or FS-DFSP. FS-DFSP tumors are more likely to metastasize than tumors in the other types of dermatofibrosarcoma protuberans.

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How many people are affected by dermatofibrosarcoma protuberans ?

Dermatofibrosarcoma protuberans is estimated to occur in 1 in 100,000 to 1 in 1 million people per year.

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What are the genetic changes related to dermatofibrosarcoma protuberans ?

Dermatofibrosarcoma protuberans is associated with a rearrangement (translocation) of genetic material between chromosomes 17 and 22. This translocation, written as t(17;22), fuses part of the COL1A1 gene from chromosome 17 with part of the PDGFB gene from chromosome 22. The translocation is found on one or more extra chromosomes that can be either the normal linear shape or circular. When circular, the extra chromosomes are known as supernumerary ring chromosomes. Ring chromosomes occur when a chromosome breaks in two places and the ends of the chromosome arms fuse together to form a circular structure. Other genes from chromosomes 17 and 22 can be found on the extra chromosomes, but the role these genes play in development of the condition is unclear. The translocation is acquired during a person's lifetime and the chromosomes containing the translocation are present only in the tumor cells. This type of genetic change is called a somatic mutation. In normal cells, the COL1A1 gene provides instructions for making part of a large molecule called type I collagen, which strengthens and supports many tissues in the body. The PDGFB gene provides instructions for making one version (isoform) of the platelet derived growth factor (PDGF) protein. By attaching to its receptor, the active PDGFB protein stimulates many cellular processes, including cell growth and division (proliferation) and maturation (differentiation). The abnormally fused COL1A1-PDGFB gene provides instructions for making an abnormal combined (fusion) protein that researchers believe ultimately functions like the PDGFB protein. The gene fusion leads to the production of an excessive amount of protein that functions like the PDGFB protein. In excess, this fusion protein stimulates cells to proliferate and differentiate abnormally, leading to the tumor formation seen in dermatofibrosarcoma protuberans. The COL1A1-PDGFB fusion gene is found in more than 90 percent of dermatofibrosarcoma protuberans cases. In the remaining cases, changes in other genes may be associated with this condition. These genes have not been identified.

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Is dermatofibrosarcoma protuberans inherited ?

Dermatofibrosarcoma protuberans results from a new mutation that occurs in the body's cells after conception and is found only in the tumor cells. This type of genetic change is called a somatic mutation and is generally not inherited.

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What are the treatments for dermatofibrosarcoma protuberans ?

These resources address the diagnosis or management of dermatofibrosarcoma protuberans: - American Cancer Society: How are Soft Tissue Sarcomas Diagnosed? - American Cancer Society: Treatment of Soft Tissue Sarcomas - Genetic Testing Registry: Dermatofibrosarcoma protuberans - National Cancer Institute: Adult Soft Tissue Sarcoma - National Cancer Institute: Targeted Cancer Therapies 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

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What is (are) 17 alpha-hydroxylase/17,20-lyase deficiency ?

17 alpha()-hydroxylase/17,20-lyase deficiency is a condition that affects the function of certain hormone-producing glands called the gonads (ovaries in females and testes in males) and the adrenal glands. The gonads direct sexual development before birth and during puberty and are important for reproduction. The adrenal glands, which are located on top of the kidneys, regulate the production of certain hormones, including those that control salt levels in the body. People with 17-hydroxylase/17,20-lyase deficiency have an imbalance of many of the hormones that are made in these glands. 17-hydroxylase/17,20-lyase deficiency is one of a group of disorders, known as congenital adrenal hyperplasias, that impair hormone production and disrupt sexual development and maturation. Hormone imbalances lead to the characteristic signs and symptoms of 17-hydroxylase/17,20-lyase deficiency, which include high blood pressure (hypertension), low levels of potassium in the blood (hypokalemia), and abnormal sexual development. The severity of the features varies. Two forms of the condition are recognized: complete 17-hydroxylase/17,20-lyase deficiency, which is more severe, and partial 17-hydroxylase/17,20-lyase deficiency, which is typically less so. Males and females are affected by disruptions to sexual development differently. Females (who have two X chromosomes) with 17-hydroxylase/17,20-lyase deficiency are born with normal external female genitalia; however, the internal reproductive organs, including the uterus and ovaries, may be underdeveloped. Women with complete 17-hydroxylase/17,20-lyase deficiency do not develop secondary sex characteristics, such as breasts and pubic hair, and do not menstruate (amenorrhea). Women with partial 17-hydroxylase/17,20-lyase deficiency may develop some secondary sex characteristics; menstruation is typically irregular or absent. Either form of the disorder results in an inability to conceive a baby (infertility). In affected individuals who are chromosomally male (having an X and a Y chromosome), problems with sexual development lead to abnormalities of the external genitalia. The most severely affected are born with characteristically female external genitalia and are generally raised as females. However, because they do not have female internal reproductive organs, these individuals have amenorrhea and do not develop female secondary sex characteristics. These individuals have testes, but they are abnormally located in the abdomen (undescended). Sometimes, complete 17-hydroxylase/17,20-lyase deficiency leads to external genitalia that do not look clearly male or clearly female (ambiguous genitalia). Males with partial 17-hydroxylase/17,20-lyase deficiency usually have abnormal male genitalia, such as a small penis (micropenis), the opening of the urethra on the underside of the penis (hypospadias), or a scrotum divided into two lobes (bifid scrotum). Males with either complete or partial 17-hydroxylase/17,20-lyase deficiency are also infertile.

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How many people are affected by 17 alpha-hydroxylase/17,20-lyase deficiency ?

17-hydroxylase/17,20-lyase deficiency accounts for about 1 percent of congenital adrenal hyperplasia cases. It is estimated to occur in 1 in 1 million people worldwide.

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What are the genetic changes related to 17 alpha-hydroxylase/17,20-lyase deficiency ?

17-hydroxylase/17,20-lyase deficiency is caused by mutations in the CYP17A1 gene. The protein produced from this gene is involved in the formation of steroid hormones. This group of hormones includes sex hormones such as testosterone and estrogen, which are needed for normal sexual development and reproduction; mineralocorticoids, which help regulate the body's salt and water balance; and glucocorticoids, which are involved in maintaining blood sugar levels and regulating the body's response to stress. Steroid hormones are produced through a series of chemical reactions. The CYP17A1 enzyme performs two important reactions in this process. The enzyme has 17 alpha()-hydroxylase activity, which is important for production of glucocorticoids and sex hormones. CYP17A1 also has 17,20-lyase activity, which is integral to the production of sex hormones. 17-hydroxylase/17,20-lyase deficiency results from a shortage (deficiency) of both enzyme activities. The amount of remaining enzyme activity determines whether a person will have the complete or partial form of the disorder. Individuals with the complete form have CYP17A1 gene mutations that result in the production of an enzyme with very little or no 17-hydroxylase and 17,20-lyase activity. People with the partial form of this condition have CYP17A1 gene mutations that allow some enzyme activity, although at reduced levels. With little or no 17-hydroxylase activity, production of glucocorticoids is impaired, and instead, mineralocorticoids are produced. An excess of these salt-regulating hormones leads to hypertension and hypokalemia. Loss of 17,20-lyase activity impairs sex hormone production. Shortage of these hormones disrupts development of the reproductive system and impairs the onset of puberty in males and females with 17-hydroxylase/17,20-lyase deficiency.

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Is 17 alpha-hydroxylase/17,20-lyase 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.

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What are the treatments for 17 alpha-hydroxylase/17,20-lyase deficiency ?

These resources address the diagnosis or management of 17 alpha-hydroxylase/17,20-lyase deficiency: - Genetic Testing Registry: Deficiency of steroid 17-alpha-monooxygenase 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

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What is (are) spastic paraplegia type 2 ?

Spastic paraplegia type 2 is part of a group of genetic disorders known as hereditary spastic paraplegias. These disorders are characterized by progressive muscle stiffness (spasticity) and the development of paralysis of the lower limbs (paraplegia). Hereditary spastic paraplegias are divided into two types: pure and complex. The pure types involve the lower limbs. The complex types involve the lower limbs and can also affect the upper limbs to a lesser degree; the structure or functioning of the brain; and the nerves connecting the brain and spinal cord to muscles and sensory cells that detect sensations such as touch, pain, heat, and sound (the peripheral nervous system). Spastic paraplegia type 2 can occur in either the pure or complex form. People with the pure form of spastic paraplegia type 2 experience spasticity in the lower limbs, usually without any additional features. People with the complex form of spastic paraplegia type 2 have lower limb spasticity and can also experience problems with movement and balance (ataxia); involuntary movements of the eyes (nystagmus); mild intellectual disability; involuntary, rhythmic shaking (tremor); and degeneration (atrophy) of the optic nerves, which carry information from the eyes to the brain. Symptoms usually become apparent between the ages of 1 and 5 years; those affected are typically able to walk and have a normal lifespan.

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How many people are affected by spastic paraplegia type 2 ?

The prevalence of all hereditary spastic paraplegias combined is estimated to be 2 to 6 in 100,000 people worldwide. Spastic paraplegia type 2 likely accounts for only a small percentage of all spastic paraplegia cases.

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What are the genetic changes related to spastic paraplegia type 2 ?

Mutations in the PLP1 gene cause spastic paraplegia 2. The PLP1 gene provides instructions for producing proteolipid protein 1 and a modified version (isoform) of proteolipid protein 1, called DM20. Proteolipid protein 1 and DM20 are primarily located in the brain and spinal cord (central nervous system) and are the main proteins found in myelin, the fatty covering that insulates nerve fibers. A lack of proteolipid protein 1 and DM20 can cause a reduction in the formation of myelin (dysmyelination) which can impair nervous system function, resulting in the signs and symptoms of spastic paraplegia type 2.

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Is spastic paraplegia type 2 inherited ?

This condition is inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. Because females have two copies of the X chromosome, one altered copy of the gene in each cell usually leads to less severe symptoms in females than in males, or may cause no symptoms at all. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. She can pass on the gene, but generally does not experience signs and symptoms of the disorder. Some females who carry a PLP1 mutation, however, may experience muscle stiffness and a decrease in intellectual function. Females with one PLP1 mutation have an increased risk of experiencing progressive deterioration of cognitive functions (dementia) later in life.

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What are the treatments for spastic paraplegia type 2 ?

These resources address the diagnosis or management of spastic paraplegia type 2: - Gene Review: Gene Review: Hereditary Spastic Paraplegia Overview - Gene Review: Gene Review: PLP1-Related Disorders - Genetic Testing Registry: Spastic paraplegia 2 - Spastic Paraplegia Foundation, Inc.: Treatments and Therapies 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

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What is (are) familial glucocorticoid deficiency ?

Familial glucocorticoid deficiency is a condition that occurs when the adrenal glands, which are hormone-producing glands located on top of each kidney, do not produce certain hormones called glucocorticoids. These hormones, which include cortisol and corticosterone, aid in immune system function, play a role in maintaining normal blood sugar levels, help trigger nerve cell signaling in the brain, and serve many other purposes in the body. A shortage of adrenal hormones (adrenal insufficiency) causes the signs and symptoms of familial glucocorticoid deficiency. These signs and symptoms often begin in infancy or early childhood. Most affected children first develop low blood sugar (hypoglycemia). These hypoglycemic children can fail to grow and gain weight at the expected rate (failure to thrive). If left untreated, hypoglycemia can lead to seizures, learning difficulties, and other neurological problems. Hypoglycemia that is left untreated for prolonged periods can lead to neurological damage and death. Other features of familial glucocorticoid deficiency can include recurrent infections and skin coloring darker than that of other family members (hyperpigmentation). There are multiple types of familial glucocorticoid deficiency, which are distinguished by their genetic cause.

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How many people are affected by familial glucocorticoid deficiency ?

The prevalence of familial glucocorticoid deficiency is unknown.

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What are the genetic changes related to familial glucocorticoid deficiency ?

Mutations in the MC2R, MRAP, and NNT genes account for the majority of cases of familial glucocorticoid deficiency; mutations in other genes, some known and some unidentified, can also cause this condition. The MC2R gene provides instructions for making a protein called adrenocorticotropic hormone (ACTH) receptor, which is found primarily in the adrenal glands. The protein produced from the MRAP gene transports the ACTH receptor from the interior of the cell to the cell membrane. When the ACTH receptor is embedded within the cell membrane, it is turned on (activated) by the MRAP protein. Activated ACTH receptor can then attach (bind) to ACTH, and this binding triggers the adrenal glands to produce glucocorticoids. MC2R gene mutations lead to the production of a receptor that cannot be transported to the cell membrane or, if it does get to the cell membrane, cannot bind to ACTH. MRAP gene mutations impair the transport of the ACTH receptor to the cell membrane. Without the binding of the ACTH receptor to its hormone, there is no signal to trigger the adrenal glands to produce glucocorticoids. The NNT gene provides instructions for making an enzyme called nicotinamide nucleotide transhydrogenase. This enzyme is found embedded in the inner membrane of structures called mitochondria, which are the energy-producing centers of cells. This enzyme helps produce a substance called NADPH, which is involved in removing potentially toxic molecules called reactive oxygen species that can damage DNA, proteins, and cell membranes. NNT gene mutations impair the enzyme's ability to produce NADPH, leading to an increase in reactive oxygen species in adrenal gland tissues. Over time, these toxic molecules can impair the function of adrenal gland cells and lead to their death (apoptosis), diminishing the production of glucocorticoids.

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Is familial glucocorticoid 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.

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What are the treatments for familial glucocorticoid deficiency ?

These resources address the diagnosis or management of familial glucocorticoid deficiency: - Genetic Testing Registry: ACTH resistance - Genetic Testing Registry: Glucocorticoid deficiency 2 - Genetic Testing Registry: Glucocorticoid deficiency 3 - Genetic Testing Registry: Glucocorticoid deficiency 4 - Genetic Testing Registry: Natural killer cell deficiency, familial isolated 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

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What is (are) multiple system atrophy ?

Multiple system atrophy is a progressive brain disorder that affects movement and balance and disrupts the function of the autonomic nervous system. The autonomic nervous system controls body functions that are mostly involuntary, such as regulation of blood pressure. Researchers have described two major types of multiple system atrophy, which are distinguished by their major signs and symptoms at the time of diagnosis. In one type, known as MSA-P, a group of movement abnormalities called parkinsonism are predominant. These abnormalities include unusually slow movement (bradykinesia), muscle rigidity, tremors, and an inability to hold the body upright and balanced (postural instability). The other type of multiple system atrophy, known as MSA-C, is characterized by cerebellar ataxia, which causes problems with coordination and balance. This form of the condition can also include speech difficulties (dysarthria) and problems controlling eye movement. Both forms of multiple system atrophy are associated with abnormalities of the autonomic nervous system. The most frequent autonomic symptoms associated with multiple system atrophy are a sudden drop in blood pressure upon standing (orthostatic hypotension), urinary difficulties, and erectile dysfunction in men. Multiple system atrophy usually occurs in older adults; on average, signs and symptoms appear around age 55. The signs and symptoms of the condition worsen with time, and affected individuals survive an average of 9 years after their diagnosis.

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How many people are affected by multiple system atrophy ?

Multiple system atrophy has a prevalence of about 2 to 5 per 100,000 people.

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What are the genetic changes related to multiple system atrophy ?

Multiple system atrophy is a complex condition that is likely caused by the interaction of multiple genetic and environmental factors. Some of these factors have been identified, but many remain unknown. Changes in several genes have been studied as possible risk factors for multiple system atrophy. The only confirmed genetic risk factors are variants in the SNCA gene. This gene provides instructions for making a protein called alpha-synuclein, which is abundant in normal brain cells but whose function is unknown. Studies suggest that several common variations in the SNCA gene are associated with an increased risk of multiple system atrophy in people of European descent. However, it is unclear how having one of these SNCA gene variants increases the risk of developing this condition. Researchers have also examined environmental factors that could contribute to the risk of multiple system atrophy. Initial studies suggested that exposure to solvents, certain types of plastic or metal, and other potential toxins might be associated with the condition. However, these associations have not been confirmed. Multiple system atrophy is characterized by clumps of abnormal alpha-synuclein protein that build up in cells in many parts of the brain and spinal cord. Over time, these clumps (which are known as inclusions) damage cells in parts of the nervous system that control movement, balance and coordination, and autonomic functioning. The progressive loss of cells in these regions underlies the major features of multiple system atrophy.

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Is multiple system atrophy inherited ?

Most cases of multiple system atrophy are sporadic, which means they occur in people with no history of the disorder in their family. Rarely, the condition has been reported to run in families; however, it does not have a clear pattern of inheritance.

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What are the treatments for multiple system atrophy ?

These resources address the diagnosis or management of multiple system atrophy: - Genetic Testing Registry: Shy-Drager syndrome - Vanderbilt Autonomic Dysfunction Center These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care

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What is (are) Meesmann corneal dystrophy ?

Meesmann corneal dystrophy is an eye disease that affects the cornea, which is the clear front covering of the eye. This condition is characterized by the formation of tiny round cysts in the outermost layer of the cornea, called the corneal epithelium. This part of the cornea acts as a barrier to help prevent foreign materials, such as dust and bacteria, from entering the eye. In people with Meesmann corneal dystrophy, cysts can appear as early as the first year of life. They usually affect both eyes and increase in number over time. The cysts usually do not cause any symptoms until late adolescence or adulthood, when they start to break open (rupture) on the surface of the cornea and cause irritation. The resulting symptoms typically include increased sensitivity to light (photophobia), twitching of the eyelids (blepharospasm), increased tear production, the sensation of having a foreign object in the eye, and an inability to tolerate wearing contact lenses. Some affected individuals also have temporary episodes of blurred vision.

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How many people are affected by Meesmann corneal dystrophy ?

Meesmann corneal dystrophy is a rare disorder whose prevalence is unknown. It was first described in a large, multi-generational German family with more than 100 affected members. Since then, the condition has been reported in individuals and families worldwide.

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