Questions
stringlengths 14
191
| Answers
stringlengths 6
29k
⌀ |
|---|---|
What are the genetic changes related to homocystinuria ?
|
Mutations in the CBS, MTHFR, MTR, MTRR, and MMADHC genes cause homocystinuria. Mutations in the CBS gene cause the most common form of homocystinuria. The CBS gene provides instructions for producing an enzyme called cystathionine beta-synthase. This enzyme acts in a chemical pathway and is responsible for converting the amino acid homocysteine to a molecule called cystathionine. As a result of this pathway, other amino acids, including methionine, are produced. Mutations in the CBS gene disrupt the function of cystathionine beta-synthase, preventing homocysteine from being used properly. As a result, this amino acid and toxic byproducts substances build up in the blood. Some of the excess homocysteine is excreted in urine. Rarely, homocystinuria can be caused by mutations in several other genes. The enzymes made by the MTHFR, MTR, MTRR, and MMADHC genes play roles in converting homocysteine to methionine. Mutations in any of these genes prevent the enzymes from functioning properly, which leads to a buildup of homocysteine in the body. Researchers have not determined how excess homocysteine and related compounds lead to the signs and symptoms of homocystinuria.
|
Is homocystinuria inherited ?
|
This condition is 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. Although people who carry one mutated copy and one normal copy of the CBS gene do not have homocystinuria, they are more likely than people without a CBS mutation to have shortages (deficiencies) of vitamin B12 and folic acid.
|
What are the treatments for homocystinuria ?
|
These resources address the diagnosis or management of homocystinuria: - Baby's First Test - Gene Review: Gene Review: Disorders of Intracellular Cobalamin Metabolism - Gene Review: Gene Review: Homocystinuria Caused by Cystathionine Beta-Synthase Deficiency - Genetic Testing Registry: Homocysteinemia due to MTHFR deficiency - Genetic Testing Registry: Homocystinuria due to CBS deficiency - Genetic Testing Registry: Homocystinuria, cblD type, variant 1 - Genetic Testing Registry: Homocystinuria-Megaloblastic anemia due to defect in cobalamin metabolism, cblE complementation type - Genetic Testing Registry: METHYLCOBALAMIN DEFICIENCY, cblG TYPE - Genetic Testing Registry: Methylmalonic acidemia with homocystinuria cblD - Genetic Testing Registry: Methylmalonic aciduria, cblD type, variant 2 - MedlinePlus Encyclopedia: Homocystinuria - New England Consortium of Metabolic Programs These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
|
What is (are) cytochrome c oxidase deficiency ?
|
Cytochrome c oxidase deficiency is a genetic condition that can affect several parts of the body, including the muscles used for movement (skeletal muscles), the heart, the brain, or the liver. Signs and symptoms of cytochrome c oxidase deficiency usually begin before age 2 but can appear later in mildly affected individuals. The severity of cytochrome c oxidase deficiency varies widely among affected individuals, even among those in the same family. People who are mildly affected tend to have muscle weakness (myopathy) and poor muscle tone (hypotonia) with no other health problems. More severely affected people have myopathy along with severe brain dysfunction (encephalomyopathy). Approximately one quarter of individuals with cytochrome c oxidase deficiency have a type of heart disease that enlarges and weakens the heart muscle (hypertrophic cardiomyopathy). Another possible feature of this condition is an enlarged liver, which may lead to liver failure. Most individuals with cytochrome c oxidase deficiency have a buildup of a chemical called lactic acid in the body (lactic acidosis), which can cause nausea and an irregular heart rate, and can be life-threatening. Many people with cytochrome c oxidase deficiency have a specific group of features known as Leigh syndrome. The signs and symptoms of Leigh syndrome include loss of mental function, movement problems, hypertrophic cardiomyopathy, eating difficulties, and brain abnormalities. Cytochrome c oxidase deficiency is one of the many causes of Leigh syndrome. Cytochrome c oxidase deficiency is frequently fatal in childhood, although some individuals with mild signs and symptoms survive into adolescence or adulthood.
|
How many people are affected by cytochrome c oxidase deficiency ?
|
In Eastern Europe, cytochrome c oxidase deficiency is estimated to occur in 1 in 35,000 individuals. The prevalence of this condition outside this region is unknown.
|
What are the genetic changes related to cytochrome c oxidase deficiency ?
|
Cytochrome c oxidase deficiency is caused by mutations in one of at least 14 genes. In humans, most genes are found in DNA in the cell's nucleus (nuclear DNA). However, some genes are found in DNA in specialized structures in the cell called mitochondria. This type of DNA is known as mitochondrial DNA (mtDNA). Most cases of cytochrome c oxidase deficiency are caused by mutations in genes found within nuclear DNA; however, in some rare instances, mutations in genes located within mtDNA cause this condition. The genes associated with cytochrome c oxidase deficiency are involved in energy production in mitochondria through a process called oxidative phosphorylation. The gene mutations that cause cytochrome c oxidase deficiency affect an enzyme complex called cytochrome c oxidase, which is responsible for one of the final steps in oxidative phosphorylation. Cytochrome c oxidase is made up of two large enzyme complexes called holoenzymes, which are each composed of multiple protein subunits. Three of these subunits are produced from mitochondrial genes; the rest are produced from nuclear genes. Many other proteins, all produced from nuclear genes, are involved in assembling these subunits into holoenzymes. Most mutations that cause cytochrome c oxidase alter proteins that assemble the holoenzymes. As a result, the holoenzymes are either partially assembled or not assembled at all. Without complete holoenzymes, cytochrome c oxidase cannot form. Mutations in the three mitochondrial genes and a few nuclear genes that provide instructions for making the holoenzyme subunits can also cause cytochrome c oxidase deficiency. Altered subunit proteins reduce the function of the holoenzymes, resulting in a nonfunctional version of cytochrome c oxidase. A lack of functional cytochrome c oxidase disrupts the last step of oxidative phosphorylation, causing a decrease in energy production. Researchers believe that impaired oxidative phosphorylation can lead to cell death by reducing the amount of energy available in the cell. Certain tissues that require large amounts of energy, such as the brain, muscles, and heart, seem especially sensitive to decreases in cellular energy. Cell death in other sensitive tissues may also contribute to the features of cytochrome c oxidase deficiency.
|
Is cytochrome c oxidase deficiency inherited ?
|
Cytochrome c oxidase deficiency can have different inheritance patterns depending on the gene involved. When this condition is caused by mutations in genes within nuclear DNA, it 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. When this condition is caused by mutations in genes within mtDNA, it is inherited in a mitochondrial pattern, which is also known as maternal inheritance. This pattern of inheritance applies to genes contained in mtDNA. Because egg cells, but not sperm cells, contribute mitochondria to the developing embryo, children can only inherit disorders resulting from mtDNA mutations from their mother. These disorders can appear in every generation of a family and can affect both males and females, but fathers do not pass traits associated with changes in mtDNA to their children.
|
What are the treatments for cytochrome c oxidase deficiency ?
|
These resources address the diagnosis or management of cytochrome c oxidase deficiency: - Cincinnati Children's Hospital: Acute Liver Failure - Cincinnati Children's Hospital: Cardiomyopathies - Genetic Testing Registry: Cardioencephalomyopathy, fatal infantile, due to cytochrome c oxidase deficiency - Genetic Testing Registry: Cytochrome-c oxidase deficiency - The United Mitochondrial Disease Foundation: 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
|
What is (are) Tourette syndrome ?
|
Tourette syndrome is a complex disorder characterized by repetitive, sudden, and involuntary movements or noises called tics. Tics usually appear in childhood, and their severity varies over time. In most cases, tics become milder and less frequent in late adolescence and adulthood. Tourette syndrome involves both motor tics, which are uncontrolled body movements, and vocal or phonic tics, which are outbursts of sound. Some motor tics are simple and involve only one muscle group. Simple motor tics, such as rapid eye blinking, shoulder shrugging, or nose twitching, are usually the first signs of Tourette syndrome. Motor tics also can be complex (involving multiple muscle groups), such as jumping, kicking, hopping, or spinning. Vocal tics, which generally appear later than motor tics, also can be simple or complex. Simple vocal tics include grunting, sniffing, and throat-clearing. More complex vocalizations include repeating the words of others (echolalia) or repeating one's own words (palilalia). The involuntary use of inappropriate or obscene language (coprolalia) is possible, but uncommon, among people with Tourette syndrome. In addition to frequent tics, people with Tourette syndrome are at risk for associated problems including attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), anxiety, depression, and problems with sleep.
|
How many people are affected by Tourette syndrome ?
|
Although the exact incidence of Tourette syndrome is uncertain, it is estimated to affect 1 to 10 in 1,000 children. This disorder occurs in populations and ethnic groups worldwide, and it is more common in males than in females.
|
What are the genetic changes related to Tourette syndrome ?
|
A variety of genetic and environmental factors likely play a role in causing Tourette syndrome. Most of these factors are unknown, and researchers are studying risk factors before and after birth that may contribute to this complex disorder. Scientists believe that tics may result from changes in brain chemicals (neurotransmitters) that are responsible for producing and controlling voluntary movements. Mutations involving the SLITRK1 gene have been identified in a small number of people with Tourette syndrome. This gene provides instructions for making a protein that is active in the brain. The SLITRK1 protein probably plays a role in the development of nerve cells, including the growth of specialized extensions (axons and dendrites) that allow each nerve cell to communicate with nearby cells. It is unclear how mutations in the SLITRK1 gene can lead to this disorder. Most people with Tourette syndrome do not have a mutation in the SLITRK1 gene. Because mutations have been reported in so few people with this condition, the association of the SLITRK1 gene with this disorder has not been confirmed. Researchers suspect that changes in other genes, which have not been identified, are also associated with Tourette syndrome.
|
Is Tourette syndrome inherited ?
|
The inheritance pattern of Tourette syndrome is unclear. Although the features of this condition can cluster in families, many genetic and environmental factors are likely to be involved. Among family members of an affected person, it is difficult to predict who else may be at risk of developing the condition. Tourette syndrome was previously thought to have an autosomal dominant pattern of inheritance, which suggests that one mutated copy of a gene in each cell would be sufficient to cause the condition. Several decades of research have shown that this is not the case. Almost all cases of Tourette syndrome probably result from a variety of genetic and environmental factors, not changes in a single gene.
|
What are the treatments for Tourette syndrome ?
|
These resources address the diagnosis or management of Tourette syndrome: - Gene Review: Gene Review: Tourette Disorder Overview - Genetic Testing Registry: Tourette Syndrome - MedlinePlus Encyclopedia: Gilles de la Tourette 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
|
What is (are) ocular albinism ?
|
Ocular albinism is a genetic condition that primarily affects the eyes. This condition reduces the coloring (pigmentation) of the iris, which is the colored part of the eye, and the retina, which is the light-sensitive tissue at the back of the eye. Pigmentation in the eye is essential for normal vision. Ocular albinism is characterized by severely impaired sharpness of vision (visual acuity) and problems with combining vision from both eyes to perceive depth (stereoscopic vision). Although the vision loss is permanent, it does not worsen over time. Other eye abnormalities associated with this condition include rapid, involuntary eye movements (nystagmus); eyes that do not look in the same direction (strabismus); and increased sensitivity to light (photophobia). Many affected individuals also have abnormalities involving the optic nerves, which carry visual information from the eye to the brain. Unlike some other forms of albinism, ocular albinism does not significantly affect the color of the skin and hair. People with this condition may have a somewhat lighter complexion than other members of their family, but these differences are usually minor. The most common form of ocular albinism is known as the Nettleship-Falls type or type 1. Other forms of ocular albinism are much rarer and may be associated with additional signs and symptoms, such as hearing loss.
|
How many people are affected by ocular albinism ?
|
The most common form of this disorder, ocular albinism type 1, affects at least 1 in 60,000 males. The classic signs and symptoms of this condition are much less common in females.
|
What are the genetic changes related to ocular albinism ?
|
Ocular albinism type 1 results from mutations in the GPR143 gene. This gene provides instructions for making a protein that plays a role in pigmentation of the eyes and skin. It helps control the growth of melanosomes, which are cellular structures that produce and store a pigment called melanin. Melanin is the substance that gives skin, hair, and eyes their color. In the retina, this pigment also plays a role in normal vision. Most mutations in the GPR143 gene alter the size or shape of the GPR143 protein. Many of these genetic changes prevent the protein from reaching melanosomes to control their growth. In other cases, the protein reaches melanosomes normally but mutations disrupt the protein's function. As a result of these changes, melanosomes in skin cells and the retina can grow abnormally large. Researchers are uncertain how these giant melanosomes are related to vision loss and other eye abnormalities in people with ocular albinism. Rare cases of ocular albinism are not caused by mutations in the GPR143 gene. In these cases, the genetic cause of the condition is often unknown.
|
Is ocular albinism inherited ?
|
Ocular albinism type 1 is inherited in an X-linked 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 GPR143 gene in each cell is sufficient to cause the characteristic features of ocular albinism. Because females have two copies of the X chromosome, women with only one copy of a GPR143 mutation in each cell usually do not experience vision loss or other significant eye abnormalities. They may have mild changes in retinal pigmentation that can be detected during an eye examination.
|
What are the treatments for ocular albinism ?
|
These resources address the diagnosis or management of ocular albinism: - Gene Review: Gene Review: Ocular Albinism, X-Linked - Genetic Testing Registry: Albinism ocular late onset sensorineural deafness - Genetic Testing Registry: Albinism, ocular, with sensorineural deafness - Genetic Testing Registry: Ocular albinism, type I - MedlinePlus Encyclopedia: Albinism 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
|
What is (are) juvenile myoclonic epilepsy ?
|
Juvenile myoclonic epilepsy is a condition characterized by recurrent seizures (epilepsy). This condition begins in childhood or adolescence, usually between ages 12 and 18, and lasts into adulthood. The most common type of seizure in people with this condition is myoclonic seizures, which cause rapid, uncontrolled muscle jerks. People with this condition may also have generalized tonic-clonic seizures (also known as grand mal seizures), which cause muscle rigidity, convulsions, and loss of consciousness. Sometimes, affected individuals have absence seizures, which cause loss of consciousness for a short period that appears as a staring spell. Typically, people with juvenile myoclonic epilepsy develop the characteristic myoclonic seizures in adolescence, then develop generalized tonic-clonic seizures a few years later. Although seizures can happen at any time, they occur most commonly in the morning, shortly after awakening. Seizures can be triggered by a lack of sleep, extreme tiredness, stress, or alcohol consumption.
|
How many people are affected by juvenile myoclonic epilepsy ?
|
Juvenile myoclonic epilepsy affects an estimated 1 in 1,000 people worldwide. Approximately 5 percent of people with epilepsy have juvenile myoclonic epilepsy.
|
What are the genetic changes related to juvenile myoclonic epilepsy ?
|
The genetics of juvenile myoclonic epilepsy are complex and not completely understood. Mutations in one of several genes can cause or increase susceptibility to this condition. The most studied of these genes are the GABRA1 gene and the EFHC1 gene, although mutations in at least three other genes have been identified in people with this condition. Many people with juvenile myoclonic epilepsy do not have mutations in any of these genes. Changes in other, unidentified genes are likely involved in this condition. A mutation in the GABRA1 gene has been identified in several members of a large family with juvenile myoclonic epilepsy. The GABRA1 gene provides instructions for making one piece, the alpha-1 (1) subunit, of the GABAA receptor protein. The GABAA receptor acts as a channel that allows negatively charged chlorine atoms (chloride ions) to cross the cell membrane. After infancy, the influx of chloride ions creates an environment in the cell that inhibits signaling between nerve cells (neurons) and prevents the brain from being overloaded with too many signals. Mutations in the GABRA1 gene lead to an altered 1 subunit and a decrease in the number of GABAA receptors available. As a result, the signaling between neurons is not controlled, which can lead to overstimulation of neurons. Researchers believe that the overstimulation of certain neurons in the brain triggers the abnormal brain activity associated with seizures. Mutations in the EFHC1 gene have been associated with juvenile myoclonic epilepsy in a small number of people. The EFHC1 gene provides instructions for making a protein that also plays a role in neuron activity, although its function is not completely understood. The EFHC1 protein is attached to another protein that acts as a calcium channel. This protein allows positively charged calcium ions to cross the cell membrane. The movement of these ions is critical for normal signaling between neurons. The EFHC1 protein is thought to help regulate the balance of calcium ions inside the cell, although the mechanism is unclear. In addition, studies show that the EFHC1 protein may be involved in the self-destruction of cells. EFHC1 gene mutations reduce the function of the EFHC1 protein. Researchers suggest that this reduction causes an increase in the number of neurons and disrupts the calcium balance. Together, these effects may lead to overstimulation of neurons and trigger seizures.
|
Is juvenile myoclonic epilepsy inherited ?
|
The inheritance pattern of juvenile myoclonic epilepsy is not completely understood. When the condition is caused by mutations in the GABRA1 gene, it is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. The inheritance pattern of juvenile myoclonic epilepsy caused by mutations in the EFHC1 gene is not known. Although juvenile myoclonic epilepsy can run in families, many cases occur in people with no family history of the disorder.
|
What are the treatments for juvenile myoclonic epilepsy ?
|
These resources address the diagnosis or management of juvenile myoclonic epilepsy: - Genetic Testing Registry: Epilepsy with grand mal seizures on awakening - Genetic Testing Registry: Epilepsy, idiopathic generalized 10 - Genetic Testing Registry: Epilepsy, idiopathic generalized 9 - Genetic Testing Registry: Epilepsy, juvenile myoclonic 5 - Genetic Testing Registry: Epilepsy, juvenile myoclonic 9 - Genetic Testing Registry: Juvenile myoclonic epilepsy - Merck Manual Consumer Version: Seizure Disorders 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
|
What is (are) Saethre-Chotzen syndrome ?
|
Saethre-Chotzen syndrome is a genetic condition characterized by the premature fusion of certain skull bones (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face. Most people with Saethre-Chotzen syndrome have prematurely fused skull bones along the coronal suture, the growth line that goes over the head from ear to ear. Other parts of the skull may be malformed as well. These changes can result in an abnormally shaped head, a high forehead, a low frontal hairline, droopy eyelids (ptosis), widely spaced eyes, and a broad nasal bridge. One side of the face may appear noticeably different from the other (facial asymmetry). Most people with Saethre-Chotzen syndrome also have small, unusually shaped ears. The signs and symptoms of Saethre-Chotzen syndrome vary widely, even among affected individuals in the same family. This condition can cause mild abnormalities of the hands and feet, such as fusion of the skin between the second and third fingers on each hand and a broad or duplicated first (big) toe. Delayed development and learning difficulties have been reported, although most people with this condition are of normal intelligence. Less common signs and symptoms of Saethre-Chotzen syndrome include short stature, abnormalities of the bones of the spine (the vertebra), hearing loss, and heart defects. Robinow-Sorauf syndrome is a condition with features similar to those of Saethre-Chotzen syndrome, including craniosynostosis and broad or duplicated great toes. It was once considered a separate disorder, but was found to result from mutations in the same gene and is now thought to be a mild variant of Saethre-Chotzen syndrome.
|
How many people are affected by Saethre-Chotzen syndrome ?
|
Saethre-Chotzen syndrome has an estimated prevalence of 1 in 25,000 to 50,000 people.
|
What are the genetic changes related to Saethre-Chotzen syndrome ?
|
Mutations in the TWIST1 gene cause Saethre-Chotzen syndrome. The TWIST1 gene provides instructions for making a protein that plays an important role in early development. This protein is a transcription factor, which means that it attaches (binds) to specific regions of DNA and helps control the activity of particular genes. The TWIST1 protein is active in cells that give rise to bones, muscles, and other tissues in the head and face. It is also involved in the development of the limbs. Mutations in the TWIST1 gene prevent one copy of the gene in each cell from making any functional protein. A shortage of the TWIST1 protein affects the development and maturation of cells in the skull, face, and limbs. These abnormalities underlie the signs and symptoms of Saethre-Chotzen syndrome, including the premature fusion of certain skull bones. A small number of cases of Saethre-Chotzen syndrome have resulted from a structural chromosomal abnormality, such as a deletion or rearrangement of genetic material, in the region of chromosome 7 that contains the TWIST1 gene. When Saethre-Chotzen syndrome is caused by a chromosomal deletion instead of a mutation within the TWIST1 gene, affected children are much more likely to have intellectual disability, developmental delay, and learning difficulties. These features are typically not seen in classic cases of Saethre-Chotzen syndrome. Researchers believe that a loss of other genes on chromosome 7 may be responsible for these additional features.
|
Is Saethre-Chotzen syndrome inherited ?
|
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. 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. Some people with a TWIST1 mutation do not have any of the obvious features of Saethre-Chotzen syndrome. These people are still at risk of passing on the gene mutation and may have a child with craniosynostosis and the other typical signs and symptoms of the condition.
|
What are the treatments for Saethre-Chotzen syndrome ?
|
These resources address the diagnosis or management of Saethre-Chotzen syndrome: - Gene Review: Gene Review: Saethre-Chotzen Syndrome - Genetic Testing Registry: Robinow Sorauf syndrome - Genetic Testing Registry: Saethre-Chotzen syndrome - MedlinePlus Encyclopedia: Craniosynostosis - MedlinePlus Encyclopedia: Skull of a Newborn (image) 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
|
What is (are) Rett syndrome ?
|
Rett syndrome is a brain disorder that occurs almost exclusively in girls. The most common form of the condition is known as classic Rett syndrome. After birth, girls with classic Rett syndrome have 6 to 18 months of apparently normal development before developing severe problems with language and communication, learning, coordination, and other brain functions. Early in childhood, affected girls lose purposeful use of their hands and begin making repeated hand wringing, washing, or clapping motions. They tend to grow more slowly than other children and have a small head size (microcephaly). Other signs and symptoms that can develop include breathing abnormalities, seizures, an abnormal side-to-side curvature of the spine (scoliosis), and sleep disturbances. Researchers have described several variant or atypical forms of Rett syndrome, which can be milder or more severe than the classic form.
|
How many people are affected by Rett syndrome ?
|
This condition affects an estimated 1 in 8,500 females.
|
What are the genetic changes related to Rett syndrome ?
|
Classic Rett syndrome and some variant forms of the condition are caused by mutations in the MECP2 gene. This gene provides instructions for making a protein (MeCP2) that is critical for normal brain function. Although the exact function of the MeCP2 protein is unclear, it is likely involved in maintaining connections (synapses) between nerve cells (neurons). It may also be necessary for the normal function of other types of brain cells. The MeCP2 protein is thought to help regulate the activity of genes in the brain. This protein may also control the production of different versions of certain proteins in brain cells. Mutations in the MECP2 gene alter the MeCP2 protein or result in the production of less protein, which appears to disrupt the normal function of neurons and other cells in the brain. Specifically, studies suggest that changes in the MeCP2 protein may reduce the activity of certain neurons and impair their ability to communicate with one another. It is unclear how these changes lead to the specific features of Rett syndrome. Several conditions with signs and symptoms overlapping those of Rett syndrome have been found to result from mutations in other genes. These conditions, including FOXG1 syndrome, were previously thought to be variant forms of Rett syndrome. However, doctors and researchers have identified some important differences between the conditions, so they are now usually considered to be separate disorders.
|
Is Rett syndrome inherited ?
|
In more than 99 percent of people with Rett syndrome, there is no history of the disorder in their family. Many of these cases result from new mutations in the MECP2 gene. A few families with more than one affected family member have been described. These cases helped researchers determine that classic Rett syndrome and variants caused by MECP2 gene mutations have an X-linked dominant pattern of inheritance. 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. The inheritance is dominant if one copy of the altered gene in each cell is sufficient to cause the condition. Males with mutations in the MECP2 gene often die in infancy. However, a small number of males with a genetic change involving MECP2 have developed signs and symptoms similar to those of Rett syndrome, including intellectual disability, seizures, and movement problems. In males, this condition is described as MECP2-related severe neonatal encephalopathy.
|
What are the treatments for Rett syndrome ?
|
These resources address the diagnosis or management of Rett syndrome: - Boston Children's Hospital - Cleveland Clinic - Gene Review: Gene Review: MECP2-Related Disorders - Genetic Testing Registry: Rett syndrome - International Rett Syndrome Foundation: Living with Rett Syndrome - MedlinePlus Encyclopedia: Rett 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
|
What is (are) Behet disease ?
|
Behet disease is an inflammatory condition that affects many parts of the body. The health problems associated with Behet disease result from widespread inflammation of blood vessels (vasculitis). This inflammation most commonly affects the mouth, genitals, skin, and eyes. Painful mouth sores called aphthous ulcers are usually the first sign of Behet disease. These sores occur on the lips and tongue and inside the cheeks. The ulcers look like common canker sores, and they typically heal within one to two weeks. About 75 percent of all people with Behet disease develop similar ulcers on the genitals. These ulcers occur most frequently on the scrotum in men and on the labia in women. Behet disease can also cause painful bumps and sores on the skin. Most affected individuals develop pus-filled bumps that resemble acne. These bumps can occur anywhere on the body. Some affected people also have red, tender nodules called erythema nodosum. These nodules usually develop on the legs but can also occur on the face, neck, and arms. An inflammation of the eye called uveitis is found in more than half of people with Behet disease. Eye problems are more common in younger people with the disease and affect men more often than women. Uveitis can result in blurry vision and an extreme sensitivity to light (photophobia). Rarely, inflammation can also cause eye pain and redness. If untreated, the eye problems associated with Behet disease can lead to blindness. Less commonly, Behet disease can affect the joints, gastrointestinal tract, large blood vessels, and brain and spinal cord (central nervous system). Central nervous system abnormalities are among the most serious complications of Behet disease. Related symptoms can include headaches, confusion, personality changes, memory loss, impaired speech, and problems with balance and movement. The signs and symptoms of Behet disease usually begin in a person's twenties or thirties, although they can appear at any age. Some affected people have relatively mild symptoms that are limited to sores in the mouth and on the genitals. Others have more severe symptoms affecting many parts of the body, including the central nervous system. The features of Behet disease typically come and go over a period of months or years. In most affected individuals, the health problems associated with this disorder improve with age.
|
How many people are affected by Behet disease ?
|
Behet disease is most common in Mediterranean countries, the Middle East, Japan, and other parts of Asia. However, it has been found in populations worldwide. The highest prevalence of Behet disease has been reported in Turkey, where the disorder affects up to 420 in 100,000 people. The disorder is much less common in northern European countries and the United States, where it generally affects fewer than 1 in 100,000 people.
|
What are the genetic changes related to Behet disease ?
|
The cause of Behet disease is unknown. The condition probably results from a combination of genetic and environmental factors, most of which have not been identified. However, a particular variation in the HLA-B gene has been strongly associated with the risk of developing Behet disease. The HLA-B gene provides instructions for making a protein that plays an important role in the immune system. The HLA-B gene is part of a family of genes 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). The HLA-B gene has many different normal variations, allowing each person's immune system to react to a wide range of foreign proteins. A variation of the HLA-B gene called HLA-B51 increases the risk of developing Behet disease. Although many people with Behet disease have the HLA-B51 variation, most people with this version of the HLA-B gene never develop the disorder. It is unknown how HLA-B51 increases the risk of developing Behet disease. Researchers have considered many other genetic and environmental factors as possible contributors to Behet disease. Studies have examined several genes related to immune system function, although no gene except HLA-B has been definitively associated with an increased risk of Behet disease. It appears likely that environmental factors, such as certain bacterial or viral infections, play a role in triggering the disease in people who are at risk. However, the influence of genetic and environmental factors on the development of this complex disorder remains unclear.
|
Is Behet disease inherited ?
|
Most cases of Behet disease are sporadic, which means they occur in people with no history of the disorder in their family. A small percentage of all cases have been reported to run in families; however, the condition does not have a clear pattern of inheritance.
|
What are the treatments for Behet disease ?
|
These resources address the diagnosis or management of Behet disease: - American Behcet's Disease Association: Diagnosis - American Behcet's Disease Association: Treatments - Genetic Testing Registry: Behcet'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
|
What is (are) mitochondrial trifunctional protein deficiency ?
|
Mitochondrial trifunctional protein deficiency is a rare condition that prevents the body from converting certain fats to energy, particularly during periods without food (fasting). Signs and symptoms of mitochondrial trifunctional protein deficiency may begin during infancy or later in life. Features that occur during infancy include feeding difficulties, lack of energy (lethargy), low blood sugar (hypoglycemia), weak muscle tone (hypotonia), and liver problems. Infants with this disorder are also at high risk for serious heart problems, breathing difficulties, coma, and sudden death. Signs and symptoms of mitochondrial trifunctional protein deficiency that may begin after infancy include hypotonia, muscle pain, a breakdown of muscle tissue, and a loss of sensation in the extremities (peripheral neuropathy). Problems related to mitochondrial trifunctional protein deficiency can be triggered by periods of fasting or by illnesses such as viral infections. This disorder is sometimes mistaken for Reye syndrome, a severe disorder that may develop in children while they appear to be recovering from viral infections such as chicken pox or flu. Most cases of Reye syndrome are associated with the use of aspirin during these viral infections.
|
How many people are affected by mitochondrial trifunctional protein deficiency ?
|
Mitochondrial trifunctional protein deficiency is a rare disorder; its incidence is unknown.
|
What are the genetic changes related to mitochondrial trifunctional protein deficiency ?
|
Mutations in the HADHA and HADHB genes cause mitochondrial trifunctional protein deficiency. These genes each provide instructions for making part of an enzyme complex called mitochondrial trifunctional protein. This enzyme complex functions in mitochondria, the energy-producing centers within cells. As the name suggests, mitochondrial trifunctional protein contains three enzymes that each perform a different function. This enzyme complex is required to break down (metabolize) a group of fats called long-chain fatty acids. Long-chain fatty acids are found in foods such as milk and certain oils. These fatty acids are stored in the body's fat tissues. Fatty acids are a major source of energy for the heart and muscles. During periods of fasting, fatty acids are also an important energy source for the liver and other tissues. Mutations in the HADHA or HADHB genes that cause mitochondrial trifunctional protein deficiency disrupt all three functions of this enzyme complex. Without enough of this enzyme complex, long-chain fatty acids from food and body fat cannot be metabolized and processed. As a result, these fatty acids are not converted to energy, which can lead to some features of this disorder, such as lethargy and hypoglycemia. Long-chain fatty acids or partially metabolized fatty acids may also build up and damage the liver, heart, and muscles. This abnormal buildup causes the other signs and symptoms of mitochondrial trifunctional protein deficiency.
|
Is mitochondrial trifunctional protein 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.
|
What are the treatments for mitochondrial trifunctional protein deficiency ?
|
These resources address the diagnosis or management of mitochondrial trifunctional protein deficiency: - Baby's First Test - Genetic Testing Registry: Mitochondrial trifunctional protein deficiency - MedlinePlus Encyclopedia: Hypoglycemia - MedlinePlus Encyclopedia: Peripheral Neuropathy 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
|
What is (are) Werner syndrome ?
|
Werner syndrome is characterized by the dramatic, rapid appearance of features associated with normal aging. Individuals with this disorder typically grow and develop normally until they reach puberty. Affected teenagers usually do not have a growth spurt, resulting in short stature. The characteristic aged appearance of individuals with Werner syndrome typically begins to develop when they are in their twenties and includes graying and loss of hair; a hoarse voice; and thin, hardened skin. They may also have a facial appearance described as "bird-like." Many people with Werner syndrome have thin arms and legs and a thick trunk due to abnormal fat deposition. As Werner syndrome progresses, affected individuals may develop disorders of aging early in life, such as cloudy lenses (cataracts) in both eyes, skin ulcers, type 2 diabetes, diminished fertility, severe hardening of the arteries (atherosclerosis), thinning of the bones (osteoporosis), and some types of cancer. It is not uncommon for affected individuals to develop multiple, rare cancers during their lifetime. People with Werner syndrome usually live into their late forties or early fifties. The most common causes of death are cancer and atherosclerosis.
|
How many people are affected by Werner syndrome ?
|
Werner syndrome is estimated to affect 1 in 200,000 individuals in the United States. This syndrome occurs more often in Japan, affecting 1 in 20,000 to 1 in 40,000 people.
|
What are the genetic changes related to Werner syndrome ?
|
Mutations in the WRN gene cause Werner syndrome. The WRN gene provides instructions for producing the Werner protein, which is thought to perform several tasks related to the maintenance and repair of DNA. This protein also assists in the process of copying (replicating) DNA in preparation for cell division. Mutations in the WRN gene often lead to the production of an abnormally short, nonfunctional Werner protein. Research suggests that this shortened protein is not transported to the cell's nucleus, where it normally interacts with DNA. Evidence also suggests that the altered protein is broken down more quickly in the cell than the normal Werner protein. Researchers do not fully understand how WRN mutations cause the signs and symptoms of Werner syndrome. Cells with an altered Werner protein may divide more slowly or stop dividing earlier than normal, causing growth problems. Also, the altered protein may allow DNA damage to accumulate, which could impair normal cell activities and cause the health problems associated with this condition.
|
Is Werner syndrome inherited ?
|
Werner syndrome is inherited in an autosomal recessive pattern, which means both copies of the WRN gene in each cell have mutations. The parents of an individual with Werner syndrome each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
|
What are the treatments for Werner syndrome ?
|
These resources address the diagnosis or management of Werner syndrome: - Gene Review: Gene Review: Werner Syndrome - Genetic Testing Registry: Werner 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
|
What is (are) Treacher Collins syndrome ?
|
Treacher Collins syndrome is a condition that affects the development of bones and other tissues of the face. The signs and symptoms of this disorder vary greatly, ranging from almost unnoticeable to severe. Most affected individuals have underdeveloped facial bones, particularly the cheek bones, and a very small jaw and chin (micrognathia). Some people with this condition are also born with an opening in the roof of the mouth called a cleft palate. In severe cases, underdevelopment of the facial bones may restrict an affected infant's airway, causing potentially life-threatening respiratory problems. People with Treacher Collins syndrome often have eyes that slant downward, sparse eyelashes, and a notch in the lower eyelids called an eyelid coloboma. Some affected individuals have additional eye abnormalities that can lead to vision loss. This condition is also characterized by absent, small, or unusually formed ears. Hearing loss occurs in about half of all affected individuals; hearing loss is caused by defects of the three small bones in the middle ear, which transmit sound, or by underdevelopment of the ear canal. People with Treacher Collins syndrome usually have normal intelligence.
|
How many people are affected by Treacher Collins syndrome ?
|
This condition affects an estimated 1 in 50,000 people.
|
What are the genetic changes related to Treacher Collins syndrome ?
|
Mutations in the TCOF1, POLR1C, or POLR1D gene can cause Treacher Collins syndrome. TCOF1 gene mutations are the most common cause of the disorder, accounting for 81 to 93 percent of all cases. POLR1C and POLR1D gene mutations cause an additional 2 percent of cases. In individuals without an identified mutation in one of these genes, the genetic cause of the condition is unknown. The proteins produced from the TCOF1, POLR1C, and POLR1D genes all appear to play important roles in the early development of bones and other tissues of the face. These proteins are involved in the production of a molecule called ribosomal RNA (rRNA), a chemical cousin of DNA. Ribosomal RNA helps assemble protein building blocks (amino acids) into new proteins, which is essential for the normal functioning and survival of cells. Mutations in the TCOF1, POLR1C, or POLR1D gene reduce the production of rRNA. Researchers speculate that a decrease in the amount of rRNA may trigger the self-destruction (apoptosis) of certain cells involved in the development of facial bones and tissues. The abnormal cell death could lead to the specific problems with facial development found in Treacher Collins syndrome. However, it is unclear why the effects of a reduction in rRNA are limited to facial development.
|
Is Treacher Collins syndrome inherited ?
|
When Treacher Collins syndrome results from mutations in the TCOF1 or POLR1D gene, it is considered an autosomal dominant condition, which means one copy of the altered gene in each cell is sufficient to cause the disorder. About 60 percent of these cases result from new mutations in the gene and occur in people with no history of the disorder in their family. In the remaining autosomal dominant cases, a person with Treacher Collins syndrome inherits the altered gene from an affected parent. When Treacher Collins syndrome is caused by mutations in the POLR1C gene, the condition has an autosomal recessive pattern of inheritance. Autosomal recessive inheritance 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.
|
What are the treatments for Treacher Collins syndrome ?
|
These resources address the diagnosis or management of Treacher Collins syndrome: - Gene Review: Gene Review: Treacher Collins Syndrome - Genetic Testing Registry: Mandibulofacial dysostosis, Treacher Collins type, autosomal recessive - Genetic Testing Registry: Treacher Collins syndrome - Genetic Testing Registry: Treacher collins syndrome 1 - Genetic Testing Registry: Treacher collins syndrome 2 - MedlinePlus Encyclopedia: Micrognathia - MedlinePlus Encyclopedia: Pinna Abnormalities and Low-Set Ears - MedlinePlus Encyclopedia: Treacher-Collins 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
|
What is (are) primary myelofibrosis ?
|
Primary myelofibrosis is a condition characterized by the buildup of scar tissue (fibrosis) in the bone marrow, the tissue that produces blood cells. Because of the fibrosis, the bone marrow is unable to make enough normal blood cells. The shortage of blood cells causes many of the signs and symptoms of primary myelofibrosis. Initially, most people with primary myelofibrosis have no signs or symptoms. Eventually, fibrosis can lead to a reduction in the number of red blood cells, white blood cells, and platelets. A shortage of red blood cells (anemia) often causes extreme tiredness (fatigue) or shortness of breath. A loss of white blood cells can lead to an increased number of infections, and a reduction of platelets can cause easy bleeding or bruising. Because blood cell formation (hematopoiesis) in the bone marrow is disrupted, other organs such as the spleen or liver may begin to produce blood cells. This process, called extramedullary hematopoiesis, often leads to an enlarged spleen (splenomegaly) or an enlarged liver (hepatomegaly). People with splenomegaly may feel pain or fullness in the abdomen, especially below the ribs on the left side. Other common signs and symptoms of primary myelofibrosis include fever, night sweats, and bone pain. Primary myelofibrosis is most commonly diagnosed in people aged 50 to 80 but can occur at any age.
|
How many people are affected by primary myelofibrosis ?
|
Primary myelofibrosis is a rare condition that affects approximately 1 in 500,000 people worldwide.
|
What are the genetic changes related to primary myelofibrosis ?
|
Mutations in the JAK2, MPL, CALR, and TET2 genes are associated with most cases of primary myelofibrosis. The JAK2 and MPL genes provide instructions for making proteins that promote the growth and division (proliferation) of blood cells. The CALR gene provides instructions for making a protein with multiple functions, including ensuring the proper folding of newly formed proteins and maintaining the correct levels of stored calcium in cells. The TET2 gene provides instructions for making a protein whose function is unknown. The proteins produced from the JAK2 and MPL genes are both part of a signaling pathway called the JAK/STAT pathway, which transmits chemical signals from outside the cell to the cell's nucleus. The protein produced from the MPL gene, called thrombopoietin receptor, turns on (activates) the pathway, and the JAK2 protein transmits signals after activation. Through the JAK/STAT pathway, these two proteins promote the proliferation of blood cells, particularly a type of blood cell known as a megakaryocyte. Mutations in either the JAK2 gene or the MPL gene that are associated with primary myelofibrosis lead to overactivation of the JAK/STAT pathway. The abnormal activation of JAK/STAT signaling leads to overproduction of abnormal megakaryocytes, and these megakaryocytes stimulate another type of cell to release collagen. Collagen is a protein that normally provides structural support for the cells in the bone marrow. However, in primary myelofibrosis, the excess collagen forms scar tissue in the bone marrow. Although mutations in the CALR gene and the TET2 gene are relatively common in primary myelofibrosis, it is unclear how these mutations are involved in the development of the condition. Some people with primary myelofibrosis do not have a mutation in any of the known genes associated with this condition. Researchers are working to identify other genes that may be involved in the condition.
|
Is primary myelofibrosis inherited ?
|
This condition is generally not inherited but arises from gene mutations that occur in early blood-forming cells after conception. These alterations are called somatic mutations.
|
What are the treatments for primary myelofibrosis ?
|
These resources address the diagnosis or management of primary myelofibrosis: - Genetic Testing Registry: Myelofibrosis - Merck Manual Professional Version: Primary Myelofibrosis - Myeloproliferative Neoplasm (MPN) Research Foundation: Primary Myelofibrosis (PMF) 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
|
What is (are) boomerang dysplasia ?
|
Boomerang dysplasia is a disorder that affects the development of bones throughout the body. Affected individuals are born with inward- and upward-turning feet (clubfeet) and dislocations of the hips, knees, and elbows. Bones in the spine, rib cage, pelvis, and limbs may be underdeveloped or in some cases absent. As a result of the limb bone abnormalities, individuals with this condition have very short arms and legs. Pronounced bowing of the upper leg bones (femurs) gives them a "boomerang" shape. Some individuals with boomerang dysplasia have a sac-like protrusion of the brain (encephalocele). They may also have an opening in the wall of the abdomen (an omphalocele) that allows the abdominal organs to protrude through the navel. Affected individuals typically have a distinctive nose that is broad with very small nostrils and an underdeveloped partition between the nostrils (septum). Individuals with boomerang dysplasia typically have an underdeveloped rib cage that affects the development and functioning of the lungs. As a result, affected individuals are usually stillborn or die shortly after birth from respiratory failure.
|
How many people are affected by boomerang dysplasia ?
|
Boomerang dysplasia is a rare disorder; its exact prevalence is unknown. Approximately 10 affected individuals have been identified.
|
What are the genetic changes related to boomerang dysplasia ?
|
Mutations in the FLNB gene cause boomerang dysplasia. The FLNB gene provides instructions for making a protein called filamin B. This protein helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Filamin B attaches (binds) to another protein called actin and helps the actin to form the branching network of filaments that makes up the cytoskeleton. It also links actin to many other proteins to perform various functions within the cell, including the cell signaling that helps determine how the cytoskeleton will change as tissues grow and take shape during development. Filamin B is especially important in the development of the skeleton before birth. It is active (expressed) in the cell membranes of cartilage-forming cells (chondrocytes). Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone (a process called ossification), except for the cartilage that continues to cover and protect the ends of bones and is present in the nose, airways (trachea and bronchi), and external ears. Filamin B appears to be important for normal cell growth and division (proliferation) and maturation (differentiation) of chondrocytes and for the ossification of cartilage. FLNB gene mutations that cause boomerang dysplasia change single protein building blocks (amino acids) in the filamin B protein or delete a small section of the protein sequence, resulting in an abnormal protein. This abnormal protein appears to have a new, atypical function that interferes with the proliferation or differentiation of chondrocytes, impairing ossification and leading to the signs and symptoms of boomerang dysplasia.
|
Is boomerang dysplasia 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. Almost all cases result from new mutations in the gene and occur in people with no history of the disorder in their family.
|
What are the treatments for boomerang dysplasia ?
|
These resources address the diagnosis or management of boomerang dysplasia: - Gene Review: Gene Review: FLNB-Related Disorders - Genetic Testing Registry: Boomerang dysplasia These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
|
What is (are) Joubert syndrome ?
|
Joubert syndrome is a disorder that affects many parts of the body. The signs and symptoms of this condition vary among affected individuals, even among members of the same family. The hallmark feature of Joubert syndrome is a brain abnormality called the molar tooth sign, which can be seen on brain imaging studies such as magnetic resonance imaging (MRI). This sign results from the abnormal development of regions near the back of the brain called the cerebellar vermis and the brainstem. The molar tooth sign got its name because the characteristic brain abnormalities resemble the cross-section of a molar tooth when seen on an MRI. Most infants with Joubert syndrome have weak muscle tone (hypotonia) in infancy, which evolves into difficulty coordinating movements (ataxia) in early childhood. Other characteristic features of the condition include episodes of unusually fast or slow breathing in infancy and abnormal eye movements. Most affected individuals have delayed development and intellectual disability, which range from mild to severe. Distinctive facial features are also characteristic of Joubert syndrome; these include a broad forehead, arched eyebrows, droopy eyelids (ptosis), widely spaced eyes, low-set ears, and a triangle-shaped mouth. Joubert syndrome can include a broad range of additional signs and symptoms. The condition is sometimes associated with other eye abnormalities (such as retinal dystrophy, which can cause vision loss), kidney disease, liver disease, skeletal abnormalities (such as the presence of extra fingers and toes), and hormone (endocrine) problems. When the characteristic features of Joubert syndrome occur in combination with one or more of these additional signs and symptoms, researchers refer to the condition as "Joubert syndrome and related disorders (JSRD)."
|
How many people are affected by Joubert syndrome ?
|
Joubert syndrome is estimated to affect between 1 in 80,000 and 1 in 100,000 newborns. However, this estimate may be too low because Joubert syndrome has such a large range of possible features and is likely underdiagnosed.
|
What are the genetic changes related to Joubert syndrome ?
|
Joubert syndrome and related disorders can be caused by mutations in at least 10 genes. The proteins produced from these genes are known or suspected to play roles in cell structures called cilia. Cilia are microscopic, finger-like projections that stick out from the surface of cells and are involved in chemical signaling. Cilia are important for the structure and function of many types of cells, including brain cells (neurons) and certain cells in the kidneys and liver. Cilia are also necessary for the perception of sensory input (such as sight, hearing, and smell). Mutations in the genes associated with Joubert syndrome and related disorders lead to problems with the structure and function of cilia. Defects in these cell structures probably disrupt important chemical signaling pathways during development. Although researchers believe that defective cilia are responsible for most of the features of these disorders, it remains unclear how they lead to specific developmental abnormalities. Mutations in the 10 genes known to be associated with Joubert syndrome and related disorders only account for about half of all cases of these conditions. In the remaining cases, the genetic cause is unknown.
|
Is Joubert syndrome inherited ?
|
Joubert syndrome typically has an autosomal recessive pattern of inheritance, which means both copies of a 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 usually do not show signs and symptoms of the condition. Rare cases of Joubert syndrome are inherited in an X-linked recessive pattern. In these cases, the causative gene is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
|
What are the treatments for Joubert syndrome ?
|
These resources address the diagnosis or management of Joubert syndrome: - Gene Review: Gene Review: Joubert Syndrome and Related Disorders - Genetic Testing Registry: Familial aplasia of the vermis - Genetic Testing Registry: Joubert syndrome 10 - Genetic Testing Registry: Joubert syndrome 2 - Genetic Testing Registry: Joubert syndrome 3 - Genetic Testing Registry: Joubert syndrome 4 - Genetic Testing Registry: Joubert syndrome 5 - Genetic Testing Registry: Joubert syndrome 6 - Genetic Testing Registry: Joubert syndrome 7 - Genetic Testing Registry: Joubert syndrome 8 - Genetic Testing Registry: Joubert syndrome 9 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
|
What is (are) lymphangioleiomyomatosis ?
|
Lymphangioleiomyomatosis (LAM) is a condition that affects the lungs, the kidneys, and the lymphatic system. The lymphatic system consists of a network of vessels that transport lymph fluid and immune cells throughout the body. LAM is found almost exclusively in women. It usually occurs as a feature of an inherited syndrome called tuberous sclerosis complex. When LAM occurs alone it is called isolated or sporadic LAM. Signs and symptoms of LAM most often appear during a woman's thirties. Affected women have an overgrowth of abnormal smooth muscle-like cells (LAM cells) in the lungs, resulting in the formation of lung cysts and the destruction of normal lung tissue. They may also have an accumulation of fluid in the cavity around the lungs (chylothorax). The lung abnormalities resulting from LAM may cause difficulty breathing (dyspnea), chest pain, and coughing, which may bring up blood (hemoptysis). Many women with this disorder have recurrent episodes of collapsed lung (spontaneous pneumothorax). The lung problems may be progressive and, without lung transplantation, may eventually lead to limitations in activities of daily living, the need for oxygen therapy, and respiratory failure. Although LAM cells are not considered cancerous, they may spread between tissues (metastasize). As a result, the condition may recur even after lung transplantation. Women with LAM may develop cysts in the lymphatic vessels of the chest and abdomen. These cysts are called lymphangioleiomyomas. Affected women may also develop tumors called angiomyolipomas made up of LAM cells, fat cells, and blood vessels. Angiomyolipomas usually develop in the kidneys. Internal bleeding is a common complication of angiomyolipomas.
|
How many people are affected by lymphangioleiomyomatosis ?
|
Sporadic LAM is estimated to occur in 2 to 5 per million women worldwide. This condition may be underdiagnosed because its symptoms are similar to those of other lung disorders such as asthma, bronchitis, and chronic obstructive pulmonary disease.
|
What are the genetic changes related to lymphangioleiomyomatosis ?
|
Mutations in the TSC1 gene or, more commonly, the TSC2 gene, cause LAM. The TSC1 and TSC2 genes provide instructions for making the proteins hamartin and tuberin, respectively. Within cells, these two proteins likely help regulate cell growth and size. The proteins act as tumor suppressors, which normally prevent cells from growing and dividing too fast or in an uncontrolled way. When both copies of the TSC1 gene are mutated in a particular cell, that cell cannot produce any functional hamartin; cells with two altered copies of the TSC2 gene are unable to produce any functional tuberin. The loss of these proteins allows the cell to grow and divide in an uncontrolled way, resulting in the tumors and cysts associated with LAM. It is not well understood why LAM occurs predominantly in women. Researchers believe that the female sex hormone estrogen may be involved in the development of the disorder.
|
Is lymphangioleiomyomatosis inherited ?
|
Sporadic LAM is not inherited. Instead, researchers suggest that it is caused by a random mutation in the TSC1 or TSC2 gene that occurs very early in development. As a result, some of the body's cells have a normal version of the gene, while others have the mutated version. This situation is called mosaicism. When a mutation occurs in the other copy of the TSC1 or TSC2 gene in certain cells during a woman's lifetime (a somatic mutation), she may develop LAM. These women typically have no history of this disorder in their family.
|
What are the treatments for lymphangioleiomyomatosis ?
|
These resources address the diagnosis or management of LAM: - Canadian Lung Association - Genetic Testing Registry: Lymphangiomyomatosis - Merck Manual for Healthcare Professionals - National Heart, Lung, and Blood Institute: How is LAM Diagnosed? - National Heart, Lung, and Blood Institute: How is LAM Treated? These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
|
What is (are) Manitoba oculotrichoanal syndrome ?
|
Manitoba oculotrichoanal syndrome is a condition involving several characteristic physical features, particularly affecting the eyes (oculo-), hair (tricho-), and anus (-anal). People with Manitoba oculotrichoanal syndrome have widely spaced eyes (hypertelorism). They may also have other eye abnormalities including small eyes (microphthalmia), a notched or partially absent upper eyelid (upper eyelid coloboma), eyelids that are attached to the front surface of the eye (corneopalpebral synechiae), or eyes that are completely covered by skin and usually malformed (cryptophthalmos). These abnormalities may affect one or both eyes. Individuals with Manitoba oculotrichoanal syndrome usually have abnormalities of the front hairline, such as hair growth extending from the temple to the eye on one or both sides of the face. One or both eyebrows may be completely or partially missing. Most people with this disorder also have a wide nose with a notched tip; in some cases this notch extends up from the tip so that the nose appears to be divided into two halves (bifid nose). About 20 percent of people with Manitoba oculotrichoanal syndrome have defects in the abdominal wall, such as a soft out-pouching around the belly-button (an umbilical hernia) or an opening in the wall of the abdomen (an omphalocele) that allows the abdominal organs to protrude through the navel. Another characteristic feature of Manitoba oculotrichoanal syndrome is a narrow anus (anal stenosis) or an anal opening farther forward than usual. Umbilical wall defects or anal malformations may require surgical correction. Some affected individuals also have malformations of the kidneys. The severity of the features of Manitoba oculotrichoanal syndrome may vary even within the same family. With appropriate treatment, affected individuals generally have normal growth and development, intelligence, and life expectancy.
|
How many people are affected by Manitoba oculotrichoanal syndrome ?
|
Manitoba oculotrichoanal syndrome is estimated to occur in 2 to 6 in 1,000 people in a small isolated Ojibway-Cree community in northern Manitoba, Canada. Although this region has the highest incidence of the condition, it has also been diagnosed in a few people from other parts of the world.
|
What are the genetic changes related to Manitoba oculotrichoanal syndrome ?
|
Manitoba oculotrichoanal syndrome is caused by mutations in the FREM1 gene. The FREM1 gene provides instructions for making a protein that is involved in the formation and organization of basement membranes, which are thin, sheet-like structures that separate and support cells in many tissues. The FREM1 protein is one of a group of proteins, including proteins called FRAS1 and FREM2, that interact during embryonic development as components of basement membranes. Basement membranes help anchor layers of cells lining the surfaces and cavities of the body (epithelial cells) to other embryonic tissues, including those that give rise to connective tissues such as skin and cartilage. The FREM1 gene mutations that have been identified in people with Manitoba oculotrichoanal syndrome delete genetic material from the FREM1 gene or result in a premature stop signal that leads to an abnormally short FREM1 protein. These mutations most likely result in a nonfunctional protein. Absence of functional FREM1 protein interferes with its role in embryonic basement membrane development and may also affect the location, stability, or function of the FRAS1 and FREM2 proteins. The features of Manitoba oculotrichoanal syndrome may result from the failure of neighboring embryonic tissues to fuse properly due to impairment of the basement membranes' anchoring function.
|
Is Manitoba oculotrichoanal 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.
|
What are the treatments for Manitoba oculotrichoanal syndrome ?
|
These resources address the diagnosis or management of Manitoba oculotrichoanal syndrome: - Gene Review: Gene Review: Manitoba Oculotrichoanal Syndrome - Genetic Testing Registry: Marles Greenberg Persaud syndrome - MedlinePlus Encyclopedia: Omphalocele Repair 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
|
What is (are) Pitt-Hopkins syndrome ?
|
Pitt-Hopkins syndrome is a condition characterized by intellectual disability and developmental delay, breathing problems, recurrent seizures (epilepsy), and distinctive facial features. People with Pitt-Hopkins syndrome have moderate to severe intellectual disability. Most affected individuals have delayed development of mental and motor skills (psychomotor delay). They are delayed in learning to walk and developing fine motor skills such as picking up small items with their fingers. People with Pitt-Hopkins syndrome typically do not develop speech; some may learn to say a few words. Many affected individuals exhibit features of autistic spectrum disorders, which are characterized by impaired communication and socialization skills. Breathing problems in individuals with Pitt-Hopkins syndrome are characterized by episodes of rapid breathing (hyperventilation) followed by periods in which breathing slows or stops (apnea). These episodes can cause a lack of oxygen in the blood, leading to a bluish appearance of the skin or lips (cyanosis). In some cases, the lack of oxygen can cause loss of consciousness. Some older individuals with Pitt-Hopkins syndrome develop widened and rounded tips of the fingers and toes (clubbing) because of recurrent episodes of decreased oxygen in the blood. The breathing problems occur only when the person is awake and typically first appear in mid-childhood, but they can begin as early as infancy. Episodes of hyperventilation and apnea can be triggered by emotions such as excitement or anxiety or by extreme tiredness (fatigue). Epilepsy occurs in most people with Pitt-Hopkins syndrome and usually begins during childhood, although it can be present from birth. Individuals with Pitt-Hopkins syndrome have distinctive facial features that include thin eyebrows, sunken eyes, a prominent nose with a high nasal bridge, a pronounced double curve of the upper lip (Cupid's bow), a wide mouth with full lips, and widely spaced teeth. The ears are usually thick and cup-shaped. Children with Pitt-Hopkins syndrome typically have a happy, excitable demeanor with frequent smiling, laughter, and hand-flapping movements. However, they can also experience anxiety and behavioral problems. Other features of Pitt-Hopkins syndrome may include constipation and other gastrointestinal problems, an unusually small head (microcephaly), nearsightedness (myopia), eyes that do not look in the same direction (strabismus), short stature, and minor brain abnormalities. Affected individuals may also have small hands and feet, a single crease across the palms of the hands, flat feet (pes planus), or unusually fleshy pads at the tips of the fingers and toes. Males with Pitt-Hopkins syndrome may have undescended testes (cryptorchidism).
|
How many people are affected by Pitt-Hopkins syndrome ?
|
Pitt-Hopkins syndrome is thought to be a very rare condition. Approximately 500 affected individuals have been reported worldwide.
|
What are the genetic changes related to Pitt-Hopkins syndrome ?
|
Mutations in the TCF4 gene cause Pitt-Hopkins syndrome. This gene provides instructions for making a protein that attaches (binds) to other proteins and then binds to specific regions of DNA to help control the activity of many other genes. On the basis of its DNA binding and gene controlling activities, the TCF4 protein is known as a transcription factor. The TCF4 protein plays a role in the maturation of cells to carry out specific functions (cell differentiation) and the self-destruction of cells (apoptosis). TCF4 gene mutations disrupt the protein's ability to bind to DNA and control the activity of certain genes. These disruptions, particularly the inability of the TCF4 protein to control the activity of genes involved in nervous system development and function, contribute to the signs and symptoms of Pitt-Hopkins syndrome. Furthermore, additional proteins interact with the TCF4 protein to carry out specific functions. When the TCF4 protein is nonfunctional, these other proteins are also unable to function normally. It is also likely that the loss of the normal proteins that are attached to the nonfunctional TCF4 proteins contribute to the features of this condition. The loss of one protein in particular, the ASCL1 protein, is thought to be associated with breathing problems in people with Pitt-Hopkins syndrome.
|
Is Pitt-Hopkins syndrome inherited ?
|
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
|
What are the treatments for Pitt-Hopkins syndrome ?
|
These resources address the diagnosis or management of Pitt-Hopkins syndrome: - Gene Review: Gene Review: Pitt-Hopkins Syndrome - Genetic Testing Registry: Pitt-Hopkins 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
|
What is (are) Parkinson disease ?
|
Parkinson disease is a progressive disorder of the nervous system. The disorder affects several regions of the brain, especially an area called the substantia nigra that controls balance and movement. Often the first symptom of Parkinson disease is trembling or shaking (tremor) of a limb, especially when the body is at rest. Typically, the tremor begins on one side of the body, usually in one hand. Tremors can also affect the arms, legs, feet, and face. Other characteristic symptoms of Parkinson disease include rigidity or stiffness of the limbs and torso, slow movement (bradykinesia) or an inability to move (akinesia), and impaired balance and coordination (postural instability). These symptoms worsen slowly over time. Parkinson disease can also affect emotions and thinking ability (cognition). Some affected individuals develop psychiatric conditions such as depression and visual hallucinations. People with Parkinson disease also have an increased risk of developing dementia, which is a decline in intellectual functions including judgment and memory. Generally, Parkinson disease that begins after age 50 is called late-onset disease. The condition is described as early-onset disease if signs and symptoms begin before age 50. Early-onset cases that begin before age 20 are sometimes referred to as juvenile-onset Parkinson disease.
|
How many people are affected by Parkinson disease ?
|
Parkinson disease affects more than 1 million people in North America and more than 4 million people worldwide. In the United States, Parkinson disease occurs in approximately 13 per 100,000 people, and about 60,000 new cases are identified each year. The late-onset form is the most common type of Parkinson disease, and the risk of developing this condition increases with age. Because more people are living longer, the number of people with this disease is expected to increase in coming decades.
|
What are the genetic changes related to Parkinson disease ?
|
Most cases of Parkinson disease probably result from a complex interaction of environmental and genetic factors. These cases are classified as sporadic and occur in people with no apparent history of the disorder in their family. The cause of these sporadic cases remains unclear. Approximately 15 percent of people with Parkinson disease have a family history of this disorder. Familial cases of Parkinson disease can be caused by mutations in the LRRK2, PARK2, PARK7, PINK1, or SNCA gene, or by alterations in genes that have not been identified. Mutations in some of these genes may also play a role in cases that appear to be sporadic (not inherited). Alterations in certain genes, including GBA and UCHL1, do not cause Parkinson disease but appear to modify the risk of developing the condition in some families. Variations in other genes that have not been identified probably also contribute to Parkinson disease risk. It is not fully understood how genetic changes cause Parkinson disease or influence the risk of developing the disorder. Many Parkinson disease symptoms occur when nerve cells (neurons) in the substantia nigra die or become impaired. Normally, these cells produce a chemical messenger called dopamine, which transmits signals within the brain to produce smooth physical movements. When these dopamine-producing neurons are damaged or die, communication between the brain and muscles weakens. Eventually, the brain becomes unable to control muscle movement. Some gene mutations appear to disturb the cell machinery that breaks down (degrades) unwanted proteins in dopamine-producing neurons. As a result, undegraded proteins accumulate, leading to the impairment or death of these cells. Other mutations may affect the function of mitochondria, the energy-producing structures within cells. As a byproduct of energy production, mitochondria make unstable molecules called free radicals that can damage cells. Cells normally counteract the effects of free radicals before they cause damage, but mutations can disrupt this process. As a result, free radicals may accumulate and impair or kill dopamine-producing neurons. In most cases of Parkinson disease, protein deposits called Lewy bodies appear in dead or dying dopamine-producing neurons. (When Lewy bodies are not present, the condition is sometimes referred to as parkinsonism.) It is unclear whether Lewy bodies play a role in killing nerve cells or if they are part of the cells' response to the disease.
|
Is Parkinson disease inherited ?
|
Most cases of Parkinson disease occur in people with no apparent family history of the disorder. These sporadic cases may not be inherited, or they may have an inheritance pattern that is unknown. Among familial cases of Parkinson disease, the inheritance pattern differs depending on the gene that is altered. If the LRRK2 or SNCA gene is involved, the disorder is inherited in an autosomal dominant pattern, which means one copy of an altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition. If the PARK2, PARK7, or PINK1 gene is involved, Parkinson disease is inherited in an autosomal recessive pattern. This type of inheritance means that two copies of the gene in each cell are altered. Most often, the parents of an individual with autosomal recessive Parkinson disease each carry one copy of the altered gene but do not show signs and symptoms of the disorder. When genetic alterations modify the risk of developing Parkinson disease, the inheritance pattern is usually unknown.
|
What are the treatments for Parkinson disease ?
|
These resources address the diagnosis or management of Parkinson disease: - Gene Review: Gene Review: Parkinson Disease Overview - Genetic Testing Registry: Parkinson disease 1 - Genetic Testing Registry: Parkinson disease 10 - Genetic Testing Registry: Parkinson disease 11 - Genetic Testing Registry: Parkinson disease 12 - Genetic Testing Registry: Parkinson disease 13 - Genetic Testing Registry: Parkinson disease 14 - Genetic Testing Registry: Parkinson disease 15 - Genetic Testing Registry: Parkinson disease 16 - Genetic Testing Registry: Parkinson disease 17 - Genetic Testing Registry: Parkinson disease 18 - Genetic Testing Registry: Parkinson disease 2 - Genetic Testing Registry: Parkinson disease 3 - Genetic Testing Registry: Parkinson disease 4 - Genetic Testing Registry: Parkinson disease 5 - Genetic Testing Registry: Parkinson disease 6, autosomal recessive early-onset - Genetic Testing Registry: Parkinson disease 7 - Genetic Testing Registry: Parkinson disease 8, autosomal dominant - Genetic Testing Registry: Parkinson disease, late-onset - Genetic Testing Registry: Parkinson disease, mitochondrial - MedlinePlus Encyclopedia: Parkinson's Disease - Michael J. Fox Foundation for Parkinson's Research: What Drugs Are Used to Treat Parkinson's Disease and How Do They Work? - National Institute of Neurological Disorders and Stroke: Deep Brain Stimulation for Parkinson's Disease - Parkinson's Disease Foundation: Diagnosis - Parkinson's Disease Foundation: Medications & 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
|
What is (are) 7q11.23 duplication syndrome ?
|
7q11.23 duplication syndrome is a condition that can cause a variety of neurological and behavioral problems as well as other abnormalities. People with 7q11.23 duplication syndrome typically have delayed development of speech and delayed motor skills such as crawling and walking. Speech problems and abnormalities in the way affected individuals walk and stand may persist throughout life. Affected individuals may also have weak muscle tone (hypotonia) and abnormal movements, such as involuntary movements of one side of the body that mirror intentional movements of the other side. Behavioral problems associated with this condition include anxiety disorders (such as social phobias and selective mutism, which is an inability to speak in certain circumstances), attention deficit hyperactivity disorder (ADHD), physical aggression, excessively defiant behavior (oppositional disorder), and autistic behaviors that affect communication and social interaction. While the majority of people with 7q11.23 duplication syndrome have low-average to average intelligence, intellectual development varies widely in this condition, from intellectual disability to, rarely, above-average intelligence. About one-fifth of people with 7q11.23 duplication syndrome experience seizures. About half of individuals with 7q11.23 duplication syndrome have enlargement (dilatation) of the blood vessel that carries blood from the heart to the rest of the body (the aorta); this enlargement can get worse over time. Aortic dilatation can lead to life-threatening complications if the wall of the aorta separates into layers (aortic dissection) or breaks open (ruptures). The characteristic appearance of people with 7q11.23 duplication syndrome can include a large head (macrocephaly) that is flattened in the back (brachycephaly), a broad forehead, straight eyebrows, and deep-set eyes with long eyelashes. The nose may be broad at the tip with the area separating the nostrils attaching lower than usual on the face (low insertion of the columella), resulting in a shortened area between the nose and the upper lip (philtrum). A high arch in the roof of the mouth (high-arched palate) and ear abnormalities may also occur in affected individuals.
|
How many people are affected by 7q11.23 duplication syndrome ?
|
The prevalence of this disorder is estimated to be 1 in 7,500 to 20,000 people.
|
What are the genetic changes related to 7q11.23 duplication syndrome ?
|
7q11.23 duplication syndrome results from an extra copy of a region on the long (q) arm of chromosome 7 in each cell. This region is called the Williams-Beuren syndrome critical region (WBSCR) because its deletion causes a different disorder called Williams syndrome, also known as Williams-Beuren syndrome. The region, which is 1.5 to 1.8 million DNA base pairs (Mb) in length, includes 26 to 28 genes. Extra copies of several of the genes in the duplicated region, including the ELN and GTF2I genes, likely contribute to the characteristic features of 7q11.23 duplication syndrome. Researchers suggest that an extra copy of the ELN gene in each cell may be related to the increased risk for aortic dilatation in 7q11.23 duplication syndrome. Studies suggest that an extra copy of the GTF2I gene may be associated with some of the behavioral features of the disorder. However, the specific causes of these features are unclear. Researchers are studying additional genes in the duplicated region, but none have been definitely linked to any of the specific signs or symptoms of 7q11.23 duplication syndrome.
|
Is 7q11.23 duplication syndrome inherited ?
|
7q11.23 duplication syndrome is considered to be an autosomal dominant condition, which means one copy of chromosome 7 with the duplication in each cell is sufficient to cause the disorder. Most cases result from a duplication that occurs during the formation of reproductive cells (eggs and sperm) or in early fetal development. These cases occur in people with no history of the disorder in their family. Less commonly, an affected person inherits the chromosome with a duplicated segment from a parent.
|
What are the treatments for 7q11.23 duplication syndrome ?
|
These resources address the diagnosis or management of 7q11.23 duplication syndrome: - Cardiff University (United Kingdom): Copy Number Variant Research - Gene Review: Gene Review: 7q11.23 Duplication Syndrome - Genetic Testing Registry: Williams-Beuren region duplication syndrome - University of Antwerp (Belgium): 7q11.23 Research Project - University of Louisville: 7q11.23 Duplication Syndrome Research - University of Toronto: 7q11.23 Duplication Syndrome Research 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
|
What is (are) alkaptonuria ?
|
Alkaptonuria is an inherited condition that causes urine to turn black when exposed to air. Ochronosis, a buildup of dark pigment in connective tissues such as cartilage and skin, is also characteristic of the disorder. This blue-black pigmentation usually appears after age 30. People with alkaptonuria typically develop arthritis, particularly in the spine and large joints, beginning in early adulthood. Other features of this condition can include heart problems, kidney stones, and prostate stones.
|
How many people are affected by alkaptonuria ?
|
This condition is rare, affecting 1 in 250,000 to 1 million people worldwide. Alkaptonuria is more common in certain areas of Slovakia (where it has an incidence of about 1 in 19,000 people) and in the Dominican Republic.
|
What are the genetic changes related to alkaptonuria ?
|
Mutations in the HGD gene cause alkaptonuria. The HGD gene provides instructions for making an enzyme called homogentisate oxidase. This enzyme helps break down the amino acids phenylalanine and tyrosine, which are important building blocks of proteins. Mutations in the HGD gene impair the enzyme's role in this process. As a result, a substance called homogentisic acid, which is produced as phenylalanine and tyrosine are broken down, accumulates in the body. Excess homogentisic acid and related compounds are deposited in connective tissues, which causes cartilage and skin to darken. Over time, a buildup of this substance in the joints leads to arthritis. Homogentisic acid is also excreted in urine, making the urine turn dark when exposed to air.
|
Is alkaptonuria 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.
|
What are the treatments for alkaptonuria ?
|
These resources address the diagnosis or management of alkaptonuria: - Gene Review: Gene Review: Alkaptonuria - Genetic Testing Registry: Alkaptonuria - MedlinePlus Encyclopedia: Alkaptonuria 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
|
What is (are) infantile neuronal ceroid lipofuscinosis ?
|
Infantile neuronal ceroid lipofuscinosis (NCL) is an inherited disorder that primarily affects the nervous system. Beginning in infancy, children with this condition have intellectual and motor disability, rarely developing the ability to speak or walk. Affected children often have muscle twitches (myoclonus), recurrent seizures (epilepsy), or vision impairment. An unusually small head (microcephaly) and progressive loss of nerve cells in the brain are also characteristic features of this disorder. Children with infantile NCL usually do not survive past childhood. Infantile NCL is one of a group of NCLs (collectively called Batten disease) that affect the nervous system and typically cause progressive problems with vision, movement, and thinking ability. The different types of NCLs are distinguished by the age at which signs and symptoms first appear.
|
How many people are affected by infantile neuronal ceroid lipofuscinosis ?
|
The incidence of infantile NCL is unknown. Collectively, all forms of NCL affect an estimated 1 in 100,000 individuals worldwide. NCLs are more common in Finland, where approximately 1 in 12,500 individuals are affected.
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.