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What is (are) congenital stromal corneal dystrophy ? | Congenital stromal corneal dystrophy is an inherited eye disorder. This condition primarily affects the cornea, which is the clear outer covering of the eye. In people with this condition, the cornea appears cloudy and may have an irregular surface. These corneal changes lead to visual impairment, including blurring, glare, and a loss of sharp vision (reduced visual acuity). Visual impairment is often associated with additional eye abnormalities, including "lazy eye" (amblyopia), eyes that do not look in the same direction (strabismus), involuntary eye movements (nystagmus), and increased sensitivity to light (photophobia). | congenital stromal corneal dystrophy |
How many people are affected by congenital stromal corneal dystrophy ? | Congenital stromal corneal dystrophy is probably very rare; only a few affected families have been reported in the medical literature. | congenital stromal corneal dystrophy |
What are the genetic changes related to congenital stromal corneal dystrophy ? | Congenital stromal corneal dystrophy is caused by mutations in the DCN gene. This gene provides instructions for making a protein called decorin, which is involved in the organization of collagens. Collagens are proteins that strengthen and support connective tissues such as skin, bone, tendons, and ligaments. In the cornea, well-organized bundles of collagen make the cornea transparent. Decorin ensures that collagen fibrils in the cornea are uniformly sized and regularly spaced. Mutations in the DCN gene lead to the production of a defective version of decorin. This abnormal protein interferes with the organization of collagen fibrils in the cornea. As poorly arranged collagen fibrils accumulate, the cornea becomes cloudy. These corneal changes lead to reduced visual acuity and related eye abnormalities. | congenital stromal corneal dystrophy |
Is congenital stromal corneal dystrophy 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. | congenital stromal corneal dystrophy |
What are the treatments for congenital stromal corneal dystrophy ? | These resources address the diagnosis or management of congenital stromal corneal dystrophy: - Gene Review: Gene Review: Congenital Stromal Corneal Dystrophy - Genetic Testing Registry: Congenital Stromal Corneal Dystrophy - MedlinePlus Encyclopedia: Cloudy Cornea These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | congenital stromal corneal dystrophy |
What is (are) Sheldon-Hall syndrome ? | Sheldon-Hall syndrome, also known as distal arthrogryposis type 2B, is a disorder characterized by joint deformities (contractures) that restrict movement in the hands and feet. The term "arthrogryposis" comes from the Greek words for joint (arthro-) and crooked or hooked (gryposis). "Distal" refers to areas of the body away from the center. The characteristic features of this condition include permanently bent fingers and toes (camptodactyly), overlapping fingers, and a hand deformity called ulnar deviation in which all of the fingers are angled outward toward the fifth (pinky) finger. Inward- and upward-turning feet (a condition called clubfoot) is also commonly seen in Sheldon-Hall syndrome. The specific hand and foot abnormalities vary among affected individuals; the abnormalities are present at birth and generally do not get worse over time. People with Sheldon-Hall syndrome also usually have distinctive facial features, which include a triangular face; outside corners of the eyes that point downward (down-slanting palpebral fissures); deep folds in the skin between the nose and lips (nasolabial folds); and a small mouth with a high, arched roof of the mouth (palate). Other features that may occur in Sheldon-Hall syndrome include extra folds of skin on the neck (webbed neck) and short stature. Sheldon-Hall syndrome does not usually affect other parts of the body, and intelligence and life expectancy are normal in this disorder. | Sheldon-Hall syndrome |
How many people are affected by Sheldon-Hall syndrome ? | The prevalence of Sheldon-Hall syndrome is unknown; however, it is thought to be the most common type of distal arthrogryposis. About 100 affected individuals have been described in the medical literature. | Sheldon-Hall syndrome |
What are the genetic changes related to Sheldon-Hall syndrome ? | Sheldon-Hall syndrome can be caused by mutations in the MYH3, TNNI2, TNNT3, or TPM2 gene. These genes provide instructions for making proteins that are involved in muscle tensing (contraction). Muscle contraction occurs when thick filaments made of proteins called myosins slide past thin filaments made of proteins called actins. The MYH3 gene provides instructions for making a myosin protein that is normally active only before birth and is important for early development of the muscles. The process of muscle contraction is controlled (regulated) by other proteins called troponins and tropomyosins, which affect the interaction of myosin and actin. Certain troponin proteins are produced from the TNNI2 and TNNT3 genes. The TPM2 gene provides instructions for making a tropomyosin protein. Mutations in the MYH3, TNNI2, TNNT3, or TPM2 gene likely interfere with normal muscle development or prevent muscle contractions from being properly controlled, resulting in the contractures and other muscle and skeletal abnormalities associated with Sheldon-Hall syndrome. It is unknown why the contractures mainly affect the hands and feet or how these gene mutations are related to other features of this disorder. | Sheldon-Hall syndrome |
Is Sheldon-Hall 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 about 50 percent of cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family. | Sheldon-Hall syndrome |
What are the treatments for Sheldon-Hall syndrome ? | These resources address the diagnosis or management of Sheldon-Hall syndrome: - Gillette Children's Hospital - NYU Langone Medical Center These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Sheldon-Hall syndrome |
What is (are) choroideremia ? | Choroideremia is a condition characterized by progressive vision loss that mainly affects males. The first symptom of this condition is usually an impairment of night vision (night blindness), which can occur in early childhood. A progressive narrowing of the field of vision (tunnel vision) follows, as well as a decrease in the ability to see details (visual acuity). These vision problems are due to an ongoing loss of cells (atrophy) in the specialized light-sensitive tissue that lines the back of the eye (retina) and a nearby network of blood vessels (the choroid). The vision impairment in choroideremia worsens over time, but the progression varies among affected individuals. However, all individuals with this condition will develop blindness, most commonly in late adulthood. | choroideremia |
How many people are affected by choroideremia ? | The prevalence of choroideremia is estimated to be 1 in 50,000 to 100,000 people. However, it is likely that this condition is underdiagnosed because of its similarities to other eye disorders. Choroideremia is thought to account for approximately 4 percent of all blindness. | choroideremia |
What are the genetic changes related to choroideremia ? | Mutations in the CHM gene cause choroideremia. The CHM gene provides instructions for producing the Rab escort protein-1 (REP-1). As an escort protein, REP-1 attaches to molecules called Rab proteins within the cell and directs them to the membranes of various cell compartments (organelles). Rab proteins are involved in the movement of proteins and organelles within cells (intracellular trafficking). Mutations in the CHM gene lead to an absence of REP-1 protein or the production of a REP-1 protein that cannot carry out its protein escort function. This lack of functional REP-1 prevents Rab proteins from reaching and attaching (binding) to the organelle membranes. Without the aid of Rab proteins in intracellular trafficking, cells die prematurely. The REP-1 protein is active (expressed) throughout the body, as is a similar protein, REP-2. Research suggests that when REP-1 is absent or nonfunctional, REP-2 can perform the protein escort duties of REP-1 in many of the body's tissues. Very little REP-2 protein is present in the retina, however, so it cannot compensate for the loss of REP-1 in this tissue. Loss of REP-1 function and subsequent misplacement of Rab proteins within the cells of the retina causes the progressive vision loss characteristic of choroideremia. | choroideremia |
Is choroideremia inherited ? | Choroideremia is inherited in an X-linked recessive pattern. The CHM 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 must be present in both copies of the gene to cause the disorder. Males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In X-linked recessive inheritance, a female with one mutated copy of the gene in each cell is called a carrier. She can pass on the altered gene, but usually does not experience signs and symptoms of the disorder. Females who carry a CHM mutation may show small areas of cell loss within the retina that can be observed during a thorough eye examination. These changes can impair vision later in life. | choroideremia |
What are the treatments for choroideremia ? | These resources address the diagnosis or management of choroideremia: - Gene Review: Gene Review: Choroideremia - Genetic Testing Registry: Choroideremia - MedlinePlus Encyclopedia: Vision - night blindness - MedlinePlus Encyclopedia: Visual field 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 | choroideremia |
What is (are) sensorineural deafness and male infertility ? | Sensorineural deafness and male infertility is a condition characterized by hearing loss and an inability to father children. Affected individuals have moderate to severe sensorineural hearing loss, which is caused by abnormalities in the inner ear. The hearing loss is typically diagnosed in early childhood and does not worsen over time. Males with this condition produce sperm that have decreased movement (motility), causing affected males to be infertile. | sensorineural deafness and male infertility |
How many people are affected by sensorineural deafness and male infertility ? | The prevalence of sensorineural deafness and male infertility is unknown. | sensorineural deafness and male infertility |
What are the genetic changes related to sensorineural deafness and male infertility ? | Sensorineural deafness and male infertility is caused by a deletion of genetic material on the long (q) arm of chromosome 15. The signs and symptoms of sensorineural deafness and male infertility are related to the loss of multiple genes in this region. The size of the deletion varies among affected individuals. Researchers have determined that the loss of a particular gene on chromosome 15, the STRC gene, is responsible for hearing loss in affected individuals. The loss of another gene, CATSPER2, in the same region of chromosome 15 is responsible for the sperm abnormalities and infertility in affected males. Researchers are working to determine how the loss of additional genes in the deleted region affects people with sensorineural deafness and male infertility. | sensorineural deafness and male infertility |
Is sensorineural deafness and male infertility inherited ? | Sensorineural deafness and male infertility is inherited in an autosomal recessive pattern, which means both copies of chromosome 15 in each cell have a deletion. The parents of an individual with sensorineural deafness and male infertility each carry one copy of the chromosome 15 deletion, but they do not show symptoms of the condition. Males with two chromosome 15 deletions in each cell have sensorineural deafness and infertility. Females with two chromosome 15 deletions in each cell have sensorineural deafness as their only symptom because the CATSPER2 gene deletions affect sperm function, and women do not produce sperm. | sensorineural deafness and male infertility |
What are the treatments for sensorineural deafness and male infertility ? | These resources address the diagnosis or management of sensorineural deafness and male infertility: - Cleveland Clinic: Male Infertility - Gene Review: Gene Review: CATSPER-Related Male Infertility - Genetic Testing Registry: Deafness, sensorineural, and male infertility - MedlinePlus Health Topic: Assisted Reproductive Technology - RESOLVE: The National Infertility Association: Semen Analysis 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 | sensorineural deafness and male infertility |
What is (are) congenital generalized lipodystrophy ? | Congenital generalized lipodystrophy (also called Berardinelli-Seip congenital lipodystrophy) is a rare condition characterized by an almost total lack of fatty (adipose) tissue in the body and a very muscular appearance. Adipose tissue is found in many parts of the body, including beneath the skin and surrounding the internal organs. It stores fat for energy and also provides cushioning. Congenital generalized lipodystrophy is part of a group of related disorders known as lipodystrophies, which are all characterized by a loss of adipose tissue. A shortage of adipose tissue leads to the storage of fat elsewhere in the body, such as in the liver and muscles, which causes serious health problems. The signs and symptoms of congenital generalized lipodystrophy are usually apparent from birth or early childhood. One of the most common features is insulin resistance, a condition in which the body's tissues are unable to recognize insulin, a hormone that normally helps to regulate blood sugar levels. Insulin resistance may develop into a more serious disease called diabetes mellitus. Most affected individuals also have high levels of fats called triglycerides circulating in the bloodstream (hypertriglyceridemia), which can lead to the development of small yellow deposits of fat under the skin called eruptive xanthomas and inflammation of the pancreas (pancreatitis). Additionally, congenital generalized lipodystrophy causes an abnormal buildup of fats in the liver (hepatic steatosis), which can result in an enlarged liver (hepatomegaly) and liver failure. Some affected individuals develop a form of heart disease called hypertrophic cardiomyopathy, which can lead to heart failure and an abnormal heart rhythm (arrhythmia) that can cause sudden death. People with congenital generalized lipodystrophy have a distinctive physical appearance. They appear very muscular because they have an almost complete absence of adipose tissue and an overgrowth of muscle tissue. A lack of adipose tissue under the skin also makes the veins appear prominent. Affected individuals tend to have a large chin, prominent bones above the eyes (orbital ridges), large hands and feet, and a prominent belly button (umbilicus). Affected females may have an enlarged clitoris (clitoromegaly), an increased amount of body hair (hirsutism), irregular menstrual periods, and multiple cysts on the ovaries, which may be related to hormonal changes. Many people with this disorder develop acanthosis nigricans, a skin condition related to high levels of insulin in the bloodstream. Acanthosis nigricans causes the skin in body folds and creases to become thick, dark, and velvety. Researchers have described four types of congenital generalized lipodystrophy, which are distinguished by their genetic cause. The types also have some differences in their typical signs and symptoms. For example, in addition to the features described above, some people with congenital generalized lipodystrophy type 1 develop cysts in the long bones of the arms and legs after puberty. Type 2 can be associated with intellectual disability, which is usually mild to moderate. Type 3 appears to cause poor growth and short stature, along with other health problems. Type 4 is associated with muscle weakness, delayed development, joint abnormalities, a narrowing of the lower part of the stomach (pyloric stenosis), and severe arrhythmia that can lead to sudden death. | congenital generalized lipodystrophy |
How many people are affected by congenital generalized lipodystrophy ? | Congenital generalized lipodystrophy has an estimated prevalence of 1 in 10 million people worldwide. Between 300 and 500 people with the condition have been described in the medical literature. Although this condition has been reported in populations around the world, it appears to be more common in certain regions of Lebanon and Brazil. | congenital generalized lipodystrophy |
What are the genetic changes related to congenital generalized lipodystrophy ? | Mutations in the AGPAT2, BSCL2, CAV1, and PTRF genes cause congenital generalized lipodystrophy types 1 through 4, respectively. The proteins produced from these genes play important roles in the development and function of adipocytes, which are the fat-storing cells in adipose tissue. Mutations in any of these genes reduce or eliminate the function of their respective proteins, which impairs the development, structure, or function of adipocytes and makes the body unable to store and use fats properly. These abnormalities of adipose tissue disrupt hormones and affect many of the body's organs, resulting in the varied signs and symptoms of congenital generalized lipodystrophy. Some of the genes associated with congenital generalized lipodystrophy also play roles in other cells and tissues. For example, the protein produced from the BSCL2 gene is also present in the brain, although its function is unknown. A loss of this protein in the brain may help explain why congenital generalized lipodystrophy type 2 is sometimes associated with intellectual disability. In some people with congenital generalized lipodystrophy, no mutations have been found in any of the genes listed above. Researchers are looking for additional genetic changes associated with this disorder. | congenital generalized lipodystrophy |
Is congenital generalized lipodystrophy 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. | congenital generalized lipodystrophy |
What are the treatments for congenital generalized lipodystrophy ? | These resources address the diagnosis or management of congenital generalized lipodystrophy: - Gene Review: Gene Review: Berardinelli-Seip Congenital Lipodystrophy - Genetic Testing Registry: Berardinelli-Seip congenital lipodystrophy - MedlinePlus Encyclopedia: Hypertrophic Cardiomypathy - University of Texas Southwestern Medical Center: Lipodystrophy These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | congenital generalized lipodystrophy |
What is (are) achromatopsia ? | Achromatopsia is a condition characterized by a partial or total absence of color vision. People with complete achromatopsia cannot perceive any colors; they see only black, white, and shades of gray. Incomplete achromatopsia is a milder form of the condition that allows some color discrimination. Achromatopsia also involves other problems with vision, including an increased sensitivity to light and glare (photophobia), involuntary back-and-forth eye movements (nystagmus), and significantly reduced sharpness of vision (low visual acuity). Affected individuals can also have farsightedness (hyperopia) or, less commonly, nearsightedness (myopia). These vision problems develop in the first few months of life. Achromatopsia is different from the more common forms of color vision deficiency (also called color blindness), in which people can perceive color but have difficulty distinguishing between certain colors, such as red and green. | achromatopsia |
How many people are affected by achromatopsia ? | Achromatopsia affects an estimated 1 in 30,000 people worldwide. Complete achromatopsia is more common than incomplete achromatopsia. Complete achromatopsia occurs frequently among Pingelapese islanders, who live on one of the Eastern Caroline Islands of Micronesia. Between 4 and 10 percent of people in this population have a total absence of color vision. | achromatopsia |
What are the genetic changes related to achromatopsia ? | Achromatopsia results from changes in one of several genes: CNGA3, CNGB3, GNAT2, PDE6C, or PDE6H. A particular CNGB3 gene mutation underlies the condition in Pingelapese islanders. Achromatopsia is a disorder of the retina, which is the light-sensitive tissue at the back of the eye. The retina contains two types of light receptor cells, called rods and cones. These cells transmit visual signals from the eye to the brain through a process called phototransduction. Rods provide vision in low light (night vision). Cones provide vision in bright light (daylight vision), including color vision. Mutations in any of the genes listed above prevent cones from reacting appropriately to light, which interferes with phototransduction. In people with complete achromatopsia, cones are nonfunctional, and vision depends entirely on the activity of rods. The loss of cone function leads to a total lack of color vision and causes the other vision problems. People with incomplete achromatopsia retain some cone function. These individuals have limited color vision, and their other vision problems tend to be less severe. Some people with achromatopsia do not have identified mutations in any of the known genes. In these individuals, the cause of the disorder is unknown. Other genetic factors that have not been identified likely contribute to this condition. | achromatopsia |
Is achromatopsia 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. | achromatopsia |
What are the treatments for achromatopsia ? | These resources address the diagnosis or management of achromatopsia: - Gene Review: Gene Review: Achromatopsia - Genetic Testing Registry: Achromatopsia - MedlinePlus Encyclopedia: Color Vision Test These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | achromatopsia |
What is (are) Nager syndrome ? | Nager syndrome is a rare condition that mainly affects the development of the face, hands, and arms. The severity of this disorder varies among affected individuals. Children with Nager syndrome are born with underdeveloped cheek bones (malar hypoplasia) and a very small lower jaw (micrognathia). They often have an opening in the roof of the mouth called a cleft palate. These abnormalities frequently cause feeding problems in infants with Nager syndrome. The airway is usually restricted due to the micrognathia, which can lead to life-threatening breathing problems. People with Nager syndrome often have eyes that slant downward, absent eyelashes, and a notch in the lower eyelids called an eyelid coloboma. Many affected individuals have small or unusually formed ears, and about 60 percent have hearing loss caused by defects in the middle ear (conductive hearing loss). Nager syndrome does not affect a person's intelligence, although speech development may be delayed due to hearing impairment. Individuals with Nager syndrome have bone abnormalities in their hands and arms. The most common abnormality is malformed or absent thumbs. Affected individuals may also have fingers that are unusually curved (clinodactyly) or fused together (syndactyly). Their forearms may be shortened due to the partial or complete absence of a bone called the radius. People with Nager syndrome sometimes have difficulty fully extending their elbows. This condition can also cause bone abnormalities in the legs and feet. Less commonly, affected individuals have abnormalities of the heart, kidneys, genitalia, and urinary tract. | Nager syndrome |
How many people are affected by Nager syndrome ? | Nager syndrome is a rare condition, although its prevalence is unknown. More than 75 cases have been reported in the medical literature. | Nager syndrome |
What are the genetic changes related to Nager syndrome ? | The cause of Nager syndrome is unknown. Although the specific genes involved have not been identified, researchers believe that this condition is caused by changes in a particular region of chromosome 9 in some families. Nager syndrome disrupts the development of structures called the first and second pharyngeal arches. The pharyngeal arches are five paired structures that form on each side of the head and neck during embryonic development. These structures develop into the bones, skin, nerves, and muscles of the head and neck. In particular, the first and second pharyngeal arches develop into the jaw, the nerves and muscles for chewing and facial expressions, the bones in the middle ear, and the outer ear. The cause of the abnormal development of the pharyngeal arches in Nager syndrome is unknown. It is also unclear why affected individuals have bone abnormalities in their arms and legs. | Nager syndrome |
Is Nager syndrome inherited ? | Most cases of Nager syndrome are sporadic, which means that they occur in people with no history of the disorder in their family. Less commonly, this condition has been found to run in families. When the disorder is familial, it can have an autosomal dominant or an autosomal recessive pattern of inheritance. Autosomal dominant inheritance means one copy of an altered gene in each cell is sufficient to cause the disorder, although no genes have been associated with Nager syndrome. In autosomal dominant Nager syndrome, an affected person usually inherits the condition from one affected parent. Autosomal recessive inheritance 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 a mutated gene, but they typically do not show signs and symptoms of the condition. Nager syndrome is thought to have an autosomal recessive inheritance pattern when unaffected parents have more than one affected child. The underlying genetic cause may differ among unrelated individuals with Nager syndrome, even among those with the same pattern of inheritance. | Nager syndrome |
What are the treatments for Nager syndrome ? | These resources address the diagnosis or management of Nager syndrome: - Genetic Testing Registry: Nager syndrome - University of California San Francisco Medical Center These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Nager syndrome |
What is (are) distal hereditary motor neuropathy, type V ? | Distal hereditary motor neuropathy, type V is a progressive disorder that affects nerve cells in the spinal cord. It results in muscle weakness and affects movement of the hands and feet. Symptoms of distal hereditary motor neuropathy, type V usually begin during adolescence, but onset varies from infancy to the mid-thirties. Cramps in the hand brought on by exposure to cold temperatures are often the initial symptom. The characteristic features of distal hereditary motor neuropathy, type V are weakness and wasting (atrophy) of muscles of the hand, specifically on the thumb side of the index finger and in the palm at the base of the thumb. Foot abnormalities, such as a high arch (pes cavus), are also common, and some affected individuals eventually develop problems with walking (gait disturbance). People with this disorder have normal life expectancies. | distal hereditary motor neuropathy, type V |
How many people are affected by distal hereditary motor neuropathy, type V ? | The incidence of distal hereditary motor neuropathy, type V is unknown. Only a small number of cases have been reported. | distal hereditary motor neuropathy, type V |
What are the genetic changes related to distal hereditary motor neuropathy, type V ? | Mutations in the BSCL2 and GARS genes cause distal hereditary motor neuropathy, type V. The BSCL2 gene provides instructions for making a protein called seipin, whose function is unknown. Mutations in the BSCL2 gene likely alter the structure of seipin, causing it to fold into an incorrect 3-dimensional shape. Research findings indicate that misfolded seipin proteins accumulate in the endoplasmic reticulum, which is a structure inside the cell that is involved in protein processing and transport. This accumulation likely damages and kills motor neurons (specialized nerve cells in the brain and spinal cord that control muscle movement), leading to muscle weakness in the hands and feet. The GARS gene provides instructions for making an enzyme called glycyl-tRNA synthetase, which is involved in the production (synthesis) of proteins. It is unclear how GARS gene mutations lead to distal hereditary motor neuropathy, type V. The mutations probably reduce the activity of glycyl-tRNA synthetase. A reduction in the activity of this enzyme may impair transmission of nerve impulses. As a result, nerve cells slowly lose the ability to communicate with muscles in the hands and feet. Mutations in other genes may also cause distal hereditary motor neuropathy, type V. | distal hereditary motor neuropathy, type V |
Is distal hereditary motor neuropathy, type V 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. Some people who have the altered gene never develop the condition, a situation known as reduced penetrance. | distal hereditary motor neuropathy, type V |
What are the treatments for distal hereditary motor neuropathy, type V ? | These resources address the diagnosis or management of distal hereditary motor neuropathy, type V: - Gene Review: Gene Review: BSCL2-Related Neurologic Disorders/Seipinopathy - Gene Review: Gene Review: GARS-Associated Axonal Neuropathy - Genetic Testing Registry: Distal hereditary motor neuronopathy type 5 - Genetic Testing Registry: Distal hereditary motor neuronopathy type 5B - MedlinePlus Encyclopedia: High-Arched Foot 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 | distal hereditary motor neuropathy, type V |
What is (are) adult-onset leukoencephalopathy with axonal spheroids and pigmented glia ? | Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a neurological condition characterized by changes to certain areas of the brain. A hallmark of ALSP is leukoencephalopathy, which is the alteration of a type of brain tissue called white matter. White matter consists of nerve fibers (axons) covered by a substance called myelin that insulates and protects them. The axons extend from nerve cells (neurons) and transmit nerve impulses throughout the body. Areas of damage to this brain tissue (white matter lesions) can be seen with magnetic resonance imaging (MRI). Another feature of ALSP is swellings called spheroids in the axons of the brain, which are a sign of axon damage. Also common in ALSP are abnormally pigmented glial cells. Glial cells are specialized brain cells that protect and maintain neurons. Damage to myelin and neurons is thought to contribute to many of the neurological signs and symptoms in people with ALSP. Symptoms of ALSP usually begin in a person's forties and worsen over time. Personality changes, including depression and a loss of social inhibitions, are among the earliest symptoms of ALSP. Affected individuals may develop memory loss and loss of executive function, which is the ability to plan and implement actions and develop problem-solving strategies. Loss of this function impairs skills such as impulse control, self-monitoring, and focusing attention appropriately. Some people with ALSP have mild seizures, usually only when the condition begins. As ALSP progresses, it causes a severe decline in thinking and reasoning abilities (dementia). Over time, motor skills are affected, and people with ALSP may have difficulty walking. Many develop a pattern of movement abnormalities known as parkinsonism, which includes unusually slow movement (bradykinesia), involuntary trembling (tremor), and muscle stiffness (rigidity). The pattern of cognitive and motor problems are variable, even among individuals in the same family, although almost all affected individuals ultimately become unable to walk, speak, and care for themselves. ALSP was previously thought to be two separate conditions, hereditary diffuse leukoencephalopathy with spheroids (HDLS) and familial pigmentary orthochromatic leukodystrophy (POLD), both of which cause very similar white matter damage and cognitive and movement problems. POLD was thought to be distinguished by the presence of pigmented glial cells and an absence of spheroids; however, people with HDLS can have pigmented cells, too, and people with POLD can have spheroids. HDLS and POLD are now considered to be part of the same disease spectrum, which researchers have recommended calling ALSP. | adult-onset leukoencephalopathy with axonal spheroids and pigmented glia |
How many people are affected by adult-onset leukoencephalopathy with axonal spheroids and pigmented glia ? | ALSP is thought to be a rare disorder, although the prevalence is unknown. Because it can be mistaken for other disorders with similar symptoms, ALSP may be underdiagnosed. | adult-onset leukoencephalopathy with axonal spheroids and pigmented glia |
What are the genetic changes related to adult-onset leukoencephalopathy with axonal spheroids and pigmented glia ? | ALSP is caused by mutations in the CSF1R gene. This gene provides instructions for making a protein called colony stimulating factor 1 receptor (CSF-1 receptor), which is found in the outer membrane of certain types of cells, including glial cells. The CSF-1 receptor triggers signaling pathways that control many important cellular processes, such as cell growth and division (proliferation) and maturation of the cell to take on specific functions (differentiation). CSF1R gene mutations in ALSP lead to an altered CSF-1 receptor protein that is likely unable to stimulate cell signaling pathways. However, it is unclear how the gene mutations lead to white matter damage or cognitive and movement problems in people with ALSP. | adult-onset leukoencephalopathy with axonal spheroids and pigmented glia |
Is adult-onset leukoencephalopathy with axonal spheroids and pigmented glia inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family. | adult-onset leukoencephalopathy with axonal spheroids and pigmented glia |
What are the treatments for adult-onset leukoencephalopathy with axonal spheroids and pigmented glia ? | These resources address the diagnosis or management of ALSP: - Gene Review: Gene Review: Adult-Onset Leukoencephalopathy with Axonal Spheroids and Pigmented Glia - Genetic Testing Registry: Hereditary diffuse leukoencephalopathy with spheroids - MedlinePlus Encyclopedia: Dementia These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | adult-onset leukoencephalopathy with axonal spheroids and pigmented glia |
What is (are) lissencephaly with cerebellar hypoplasia ? | Lissencephaly with cerebellar hypoplasia (LCH) affects brain development, resulting in the brain having a smooth appearance (lissencephaly) instead of its normal folds and grooves. In addition, the part of the brain that coordinates movement is unusually small and underdeveloped (cerebellar hypoplasia). Other parts of the brain are also often underdeveloped in LCH, including the hippocampus, which plays a role in learning and memory, and the part of the brain that is connected to the spinal cord (the brainstem). Individuals with LCH have moderate to severe intellectual disability and delayed development. They have few or no communication skills, extremely poor muscle tone (hypotonia), problems with coordination and balance (ataxia), and difficulty sitting or standing without support. Most affected children experience recurrent seizures (epilepsy) that begin within the first months of life. Some affected individuals have nearsightedness (myopia), involuntary eye movements (nystagmus), or puffiness or swelling caused by a buildup of fluids in the body's tissues (lymphedema). | lissencephaly with cerebellar hypoplasia |
How many people are affected by lissencephaly with cerebellar hypoplasia ? | LCH is a rare condition, although its prevalence is unknown. | lissencephaly with cerebellar hypoplasia |
What are the genetic changes related to lissencephaly with cerebellar hypoplasia ? | LCH can be caused by mutations in the RELN or TUBA1A gene. The RELN gene provides instructions for making a protein called reelin. In the developing brain, reelin turns on (activates) a signaling pathway that triggers nerve cells (neurons) to migrate to their proper locations. The protein produced from the TUBA1A gene is also involved in neuronal migration as a component of cell structures called microtubules. Microtubules are rigid, hollow fibers that make up the cell's structural framework (the cytoskeleton). Microtubules form scaffolding within the cell that elongates in a specific direction, altering the cytoskeleton and moving neurons. Mutations in either the RELN or TUBA1A gene impair the normal migration of neurons during fetal development. As a result, neurons are disorganized, the normal folds and grooves of the brain do not form, and brain structures do not develop properly. This impairment of brain development leads to the neurological problems characteristic of LCH. | lissencephaly with cerebellar hypoplasia |
Is lissencephaly with cerebellar hypoplasia inherited ? | When LCH is caused by mutations in the RELN gene, the 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. When LCH is caused by mutations in the TUBA1A gene, the condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most of these cases result from new mutations in the gene and occur in people with no history of the disorder in their family. | lissencephaly with cerebellar hypoplasia |
What are the treatments for lissencephaly with cerebellar hypoplasia ? | These resources address the diagnosis or management of lissencephaly with cerebellar hypoplasia: - Genetic Testing Registry: Lissencephaly 2 - Genetic Testing Registry: Lissencephaly 3 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | lissencephaly with cerebellar hypoplasia |
What is (are) lymphedema-distichiasis syndrome ? | Lymphedema-distichiasis syndrome is a condition that affects the normal function of the lymphatic system, which is a part of the circulatory and immune systems. The lymphatic system produces and transports fluids and immune cells throughout the body. People with lymphedema-distichiasis syndrome develop puffiness or swelling (lymphedema) of the limbs, typically the legs and feet. Another characteristic of this syndrome is the growth of extra eyelashes (distichiasis), ranging from a few extra eyelashes to a full extra set on both the upper and lower lids. These eyelashes do not grow along the edge of the eyelid, but out of its inner lining. When the abnormal eyelashes touch the eyeball, they can cause damage to the clear covering of the eye (cornea). Related eye problems can include an irregular curvature of the cornea causing blurred vision (astigmatism) or scarring of the cornea. Other health problems associated with this disorder include swollen and knotted (varicose) veins, droopy eyelids (ptosis), heart abnormalities, and an opening in the roof of the mouth (a cleft palate). All people with lymphedema-distichiasis syndrome have extra eyelashes present at birth. The age of onset of lymphedema varies, but it most often begins during puberty. Males usually develop lymphedema earlier than females, but all affected individuals will develop lymphedema by the time they are in their forties. | lymphedema-distichiasis syndrome |
How many people are affected by lymphedema-distichiasis syndrome ? | The prevalence of lymphedema-distichiasis syndrome is unknown. Because the extra eyelashes can be overlooked during a medical examination, researchers believe that some people with this condition may be misdiagnosed as having lymphedema only. | lymphedema-distichiasis syndrome |
What are the genetic changes related to lymphedema-distichiasis syndrome ? | Lymphedema-distichiasis syndrome is caused by mutations in the FOXC2 gene. The FOXC2 gene provides instructions for making a protein that plays a critical role in the formation of many organs and tissues before birth. The FOXC2 protein is a transcription factor, which means that it attaches (binds) to specific regions of DNA and helps control the activity of many other genes. Researchers believe that the FOXC2 protein has a role in a variety of developmental processes, such as the formation of veins and the development of the lungs, eyes, kidneys and urinary tract, cardiovascular system, and the transport system for immune cells (lymphatic vessels). | lymphedema-distichiasis syndrome |
Is lymphedema-distichiasis 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. | lymphedema-distichiasis syndrome |
What are the treatments for lymphedema-distichiasis syndrome ? | These resources address the diagnosis or management of lymphedema-distichiasis syndrome: - Gene Review: Gene Review: Lymphedema-Distichiasis Syndrome - Genetic Testing Registry: Distichiasis-lymphedema syndrome - MedlinePlus Encyclopedia: Lymph System 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 | lymphedema-distichiasis syndrome |
What is (are) autosomal recessive spastic ataxia of Charlevoix-Saguenay ? | Autosomal recessive spastic ataxia of Charlevoix-Saguenay, more commonly known as ARSACS, is a condition affecting muscle movement. People with ARSACS typically have abnormal tensing of the muscles (spasticity), difficulty coordinating movements (ataxia), muscle wasting (amyotrophy), involuntary eye movements (nystagmus), and speech difficulties (dysarthria). Other problems may include deformities of the fingers and feet, reduced sensation and weakness in the arms and legs (peripheral neuropathy), yellow streaks of fatty tissue in the light-sensitive tissue at the back of the eye (hypermyelination of the retina), and less commonly, leaks in one of the valves that control blood flow through the heart (mitral valve prolapse). An unsteady gait is the first symptom of ARSACS. It usually appears between the age of 12 months and 18 months, as toddlers are learning to walk. The signs and symptoms worsen over the years, with increased spasticity and ataxia of the arms and legs. In some cases spasticity disappears, but this apparent improvement is thought to be due to degeneration of nerves in the arms and legs. Most affected individuals require a wheelchair by the time they are in their thirties or forties. This condition was first seen in people of the Charlevoix-Saguenay region of Quebec, Canada. The majority of people with ARSACS live in Quebec or have recent ancestors from Quebec. People with ARSACS have also been identified in Japan, Turkey, Tunisia, Spain, Italy, and Belgium. The signs and symptoms of ARSACS seen in other countries differ from those in Quebec. In people with ARSACS outside of Quebec, hypermyelination of the retina is seen less often, intelligence may be below normal, and symptoms tend to appear at a later age. | autosomal recessive spastic ataxia of Charlevoix-Saguenay |
How many people are affected by autosomal recessive spastic ataxia of Charlevoix-Saguenay ? | The incidence of ARSACS in the Charlevoix-Saguenay region of Quebec is estimated to be 1 in 1,500 to 2,000 individuals. Outside of Quebec, ARSACS is rare, but the incidence is unknown. | autosomal recessive spastic ataxia of Charlevoix-Saguenay |
What are the genetic changes related to autosomal recessive spastic ataxia of Charlevoix-Saguenay ? | Mutations in the SACS gene cause ARSACS. The SACS gene provides instructions for producing a protein called sacsin. Sacsin is found in the brain, skin cells, muscles used for movement (skeletal muscles), and at low levels in the pancreas, but the specific function of the protein is unknown. Research suggests that sacsin might play a role in folding newly produced proteins into the proper 3-dimensional shape because it shares similar regions with other proteins that perform this function. Mutations in the SACS gene cause the production of an unstable sacsin protein that does not function normally. It is unclear how the abnormal sacsin protein affects the brain and skeletal muscles and results in the signs and symptoms of ARSACS. | autosomal recessive spastic ataxia of Charlevoix-Saguenay |
Is autosomal recessive spastic ataxia of Charlevoix-Saguenay 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. | autosomal recessive spastic ataxia of Charlevoix-Saguenay |
What are the treatments for autosomal recessive spastic ataxia of Charlevoix-Saguenay ? | These resources address the diagnosis or management of ARSACS: - Gene Review: Gene Review: ARSACS - Genetic Testing Registry: Spastic ataxia Charlevoix-Saguenay type 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 | autosomal recessive spastic ataxia of Charlevoix-Saguenay |
What is (are) ataxia-telangiectasia ? | Ataxia-telangiectasia is a rare inherited disorder that affects the nervous system, immune system, and other body systems. This disorder is characterized by progressive difficulty with coordinating movements (ataxia) beginning in early childhood, usually before age 5. Affected children typically develop difficulty walking, problems with balance and hand coordination, involuntary jerking movements (chorea), muscle twitches (myoclonus), and disturbances in nerve function (neuropathy). The movement problems typically cause people to require wheelchair assistance by adolescence. People with this disorder also have slurred speech and trouble moving their eyes to look side-to-side (oculomotor apraxia). Small clusters of enlarged blood vessels called telangiectases, which occur in the eyes and on the surface of the skin, are also characteristic of this condition. Affected individuals tend to have high amounts of a protein called alpha-fetoprotein (AFP) in their blood. The level of this protein is normally increased in the bloodstream of pregnant women, but it is unknown why individuals with ataxia-telangiectasia have elevated AFP or what effects it has in these individuals. People with ataxia-telangiectasia often have a weakened immune system, and many develop chronic lung infections. They also have an increased risk of developing cancer, particularly cancer of blood-forming cells (leukemia) and cancer of immune system cells (lymphoma). Affected individuals are very sensitive to the effects of radiation exposure, including medical x-rays. The life expectancy of people with ataxia-telangiectasia varies greatly, but affected individuals typically live into early adulthood. | ataxia-telangiectasia |
How many people are affected by ataxia-telangiectasia ? | Ataxia-telangiectasia occurs in 1 in 40,000 to 100,000 people worldwide. | ataxia-telangiectasia |
What are the genetic changes related to ataxia-telangiectasia ? | Mutations in the ATM gene cause ataxia-telangiectasia. The ATM gene provides instructions for making a protein that helps control cell division and is involved in DNA repair. This protein plays an important role in the normal development and activity of several body systems, including the nervous system and immune system. The ATM protein assists cells in recognizing damaged or broken DNA strands and coordinates DNA repair by activating enzymes that fix the broken strands. Efficient repair of damaged DNA strands helps maintain the stability of the cell's genetic information. Mutations in the ATM gene reduce or eliminate the function of the ATM protein. Without this protein, cells become unstable and die. Cells in the part of the brain involved in coordinating movements (the cerebellum) are particularly affected by loss of the ATM protein. The loss of these brain cells causes some of the movement problems characteristic of ataxia-telangiectasia. Mutations in the ATM gene also prevent cells from responding correctly to DNA damage, which allows breaks in DNA strands to accumulate and can lead to the formation of cancerous tumors. | ataxia-telangiectasia |
Is ataxia-telangiectasia inherited ? | Ataxia-telangiectasia is inherited in an autosomal recessive pattern, which means both copies of the ATM 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. About 1 percent of the United States population carries one mutated copy and one normal copy of the ATM gene in each cell. These individuals are called carriers. Although ATM mutation carriers do not have ataxia-telangiectasia, they are more likely than people without an ATM mutation to develop cancer; female carriers are particularly at risk for developing breast cancer. Carriers of a mutation in the ATM gene also may have an increased risk of heart disease. | ataxia-telangiectasia |
What are the treatments for ataxia-telangiectasia ? | These resources address the diagnosis or management of ataxia-telangiectasia: - Gene Review: Gene Review: Ataxia-Telangiectasia - Genetic Testing Registry: Ataxia-telangiectasia syndrome - MedlinePlus Encyclopedia: Ataxia-Telangiectasia 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 | ataxia-telangiectasia |
What is (are) Leber congenital amaurosis ? | Leber congenital amaurosis is an eye disorder that primarily affects the retina, which is the specialized tissue at the back of the eye that detects light and color. People with this disorder typically have severe visual impairment beginning in infancy. The visual impairment tends to be stable, although it may worsen very slowly over time. Leber congenital amaurosis is also associated with other vision problems, including an increased sensitivity to light (photophobia), involuntary movements of the eyes (nystagmus), and extreme farsightedness (hyperopia). The pupils, which usually expand and contract in response to the amount of light entering the eye, do not react normally to light. Instead, they expand and contract more slowly than normal, or they may not respond to light at all. Additionally, the clear front covering of the eye (the cornea) may be cone-shaped and abnormally thin, a condition known as keratoconus. A specific behavior called Franceschetti's oculo-digital sign is characteristic of Leber congenital amaurosis. This sign consists of poking, pressing, and rubbing the eyes with a knuckle or finger. Researchers suspect that this behavior may contribute to deep-set eyes and keratoconus in affected children. In rare cases, delayed development and intellectual disability have been reported in people with the features of Leber congenital amaurosis. However, researchers are uncertain whether these individuals actually have Leber congenital amaurosis or another syndrome with similar signs and symptoms. At least 13 types of Leber congenital amaurosis have been described. The types are distinguished by their genetic cause, patterns of vision loss, and related eye abnormalities. | Leber congenital amaurosis |
How many people are affected by Leber congenital amaurosis ? | Leber congenital amaurosis occurs in 2 to 3 per 100,000 newborns. It is one of the most common causes of blindness in children. | Leber congenital amaurosis |
What are the genetic changes related to Leber congenital amaurosis ? | Leber congenital amaurosis can result from mutations in at least 14 genes, all of which are necessary for normal vision. These genes play a variety of roles in the development and function of the retina. For example, some of the genes associated with this disorder are necessary for the normal development of light-detecting cells called photoreceptors. Other genes are involved in phototransduction, the process by which light entering the eye is converted into electrical signals that are transmitted to the brain. Still other genes play a role in the function of cilia, which are microscopic finger-like projections that stick out from the surface of many types of cells. Cilia are necessary for the perception of several types of sensory input, including vision. Mutations in any of the genes associated with Leber congenital amaurosis disrupt the development and function of the retina, resulting in early vision loss. Mutations in the CEP290, CRB1, GUCY2D, and RPE65 genes are the most common causes of the disorder, while mutations in the other genes generally account for a smaller percentage of cases. In about 30 percent of all people with Leber congenital amaurosis, the cause of the disorder is unknown. | Leber congenital amaurosis |
Is Leber congenital amaurosis inherited ? | Leber congenital amaurosis usually 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. When Leber congenital amaurosis is caused by mutations in the CRX or IMPDH1 genes, the disorder has an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder. In most of these cases, an affected person inherits a gene mutation from one affected parent. Other cases result from new mutations and occur in people with no history of the disorder in their family. | Leber congenital amaurosis |
What are the treatments for Leber congenital amaurosis ? | These resources address the diagnosis or management of Leber congenital amaurosis: - Gene Review: Gene Review: Leber Congenital Amaurosis - Genetic Testing Registry: Leber congenital amaurosis 1 - Genetic Testing Registry: Leber congenital amaurosis 10 - Genetic Testing Registry: Leber congenital amaurosis 12 - Genetic Testing Registry: Leber congenital amaurosis 13 - Genetic Testing Registry: Leber congenital amaurosis 14 - Genetic Testing Registry: Leber congenital amaurosis 2 - Genetic Testing Registry: Leber congenital amaurosis 3 - Genetic Testing Registry: Leber congenital amaurosis 4 - Genetic Testing Registry: Leber congenital amaurosis 5 - Genetic Testing Registry: Leber congenital amaurosis 9 - Genetic Testing Registry: Leber's amaurosis - National Eye Institute: Gene Therapy for Leber Congenital Amaurosis 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 | Leber congenital amaurosis |
What is (are) tibial muscular dystrophy ? | Tibial muscular dystrophy is a condition that affects the muscles at the front of the lower leg. The signs and symptoms of this condition typically appear after age 35. The first sign is usually weakness and wasting (atrophy) of a muscle in the lower leg called the tibialis anterior. This muscle helps control up-and-down movement of the foot. Weakness in the tibialis anterior muscle makes it difficult or impossible to walk on the heels, but it usually does not interfere significantly with regular walking. Muscle weakness worsens very slowly in people with tibial muscular dystrophy. Ten to 20 years after the onset of symptoms, weakness may develop in muscles that help extend the toes (long-toe extensors). Weakness in these muscles makes it difficult to lift the toes while walking, a condition known as foot drop. Later in life, about one third of people with tibial muscular dystrophy experience mild to moderate difficulty with walking because of weakness in other leg muscles. However, most affected individuals remain able to walk throughout their lives. A small percentage of people with tibial muscular dystrophy have a somewhat different pattern of signs and symptoms than those described above. Starting in childhood, these individuals may have generalized muscle weakness, weakness and atrophy of the thigh muscles (quadriceps) or other muscles in the legs, and weakness affecting muscles in the arms. | tibial muscular dystrophy |
How many people are affected by tibial muscular dystrophy ? | Tibial muscular dystrophy is most common in Finland, where it is estimated to affect at least 10 per 100,000 people. This condition has also been found in people of Finnish descent living in other countries. Additionally, tibial muscular dystrophy has been identified in several European families without Finnish ancestry. | tibial muscular dystrophy |
What are the genetic changes related to tibial muscular dystrophy ? | Mutations in the TTN gene cause tibial muscular dystrophy. This gene provides instructions for making a protein called titin. Titin plays an important role in muscles the body uses for movement (skeletal muscles) and in heart (cardiac) muscle. Within muscle cells, titin is an essential component of structures called sarcomeres. Sarcomeres are the basic units of muscle contraction; they are made of proteins that generate the mechanical force needed for muscles to contract. Titin has several functions within sarcomeres. One of its most important jobs is to provide structure, flexibility, and stability to these cell structures. Titin also plays a role in chemical signaling and in assembling new sarcomeres. Mutations in the TTN gene alter the structure and function of titin. Researchers suspect that these changes may disrupt titin's interactions with other proteins within sarcomeres. Mutations may also interfere with the protein's role in chemical signaling. The altered titin protein disrupts normal muscle contraction, which causes muscles to weaken and waste away over time. It is unclear why these effects are usually limited to muscles in the lower legs. | tibial muscular dystrophy |
Is tibial muscular dystrophy 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. | tibial muscular dystrophy |
What are the treatments for tibial muscular dystrophy ? | These resources address the diagnosis or management of tibial muscular dystrophy: - Gene Review: Gene Review: Udd Distal Myopathy - Genetic Testing Registry: Distal myopathy Markesbery-Griggs type 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 | tibial muscular dystrophy |
What is (are) pseudohypoaldosteronism type 1 ? | Pseudohypoaldosteronism type 1 (PHA1) is a condition characterized by problems regulating the amount of sodium in the body. Sodium regulation, which is important for blood pressure and fluid balance, primarily occurs in the kidneys. However, sodium can also be removed from the body through other tissues, such as the sweat glands and colon. Pseudohypoaldosteronism type 1 is named for its characteristic signs and symptoms, which mimic (pseudo) low levels (hypo) of a hormone called aldosterone that helps regulate sodium levels. However, people with PHA1 have high levels of aldosterone. There are two types of PHA1 distinguished by their severity, the genes involved, and how they are inherited. One type, called autosomal dominant PHA1 (also known as renal PHA1) is characterized by excessive sodium loss from the kidneys. This form of the condition is relatively mild and often improves in early childhood. The other type, called autosomal recessive PHA1 (also known as generalized or systemic PHA1) is characterized by sodium loss from the kidneys and other organs, including the sweat glands, salivary glands, and colon. This type of PHA1 is more severe and does not improve with age. The earliest signs of both types of PHA1 are usually the inability to gain weight and grow at the expected rate (failure to thrive) and dehydration, which are typically seen in infants. The characteristic features of both types of PHA1 are excessive amounts of sodium released in the urine (salt wasting), which leads to low levels of sodium in the blood (hyponatremia), and high levels of potassium in the blood (hyperkalemia). Infants with PHA1 can also have high levels of acid in the blood (metabolic acidosis). Hyponatremia, hyperkalemia, or metabolic acidosis can cause nonspecific symptoms such as nausea, vomiting, extreme tiredness (fatigue), and muscle weakness in infants with PHA1. Infants with autosomal recessive PHA1 can have additional signs and symptoms due to the involvement of multiple organs. Affected individuals may experience episodes of abnormal heartbeat (cardiac arrhythmia) or shock because of the imbalance of salts in the body. They may also have recurrent lung infections or lesions on the skin. Although adults with autosomal recessive PHA1 can have repeated episodes of salt wasting, they do not usually have other signs and symptoms of the condition. | pseudohypoaldosteronism type 1 |
How many people are affected by pseudohypoaldosteronism type 1 ? | PHA1 is a rare condition that has been estimated to affect 1 in 80,000 newborns. | pseudohypoaldosteronism type 1 |
What are the genetic changes related to pseudohypoaldosteronism type 1 ? | Mutations in one of four different genes involved in sodium regulation cause autosomal dominant or autosomal recessive PHA1. Mutations in the NR3C2 gene cause autosomal dominant PHA1. This gene provides instructions for making the mineralocorticoid receptor protein. Mutations in the SCNN1A, SCNN1B, or SCNN1G genes cause autosomal recessive PHA1. Each of these three genes provides instructions for making one of the pieces (subunits) of a protein complex called the epithelial sodium channel (ENaC). The mineralocorticoid receptor regulates specialized proteins in the cell membrane that control the transport of sodium or potassium into cells. In response to signals that sodium levels are low, such as the presence of the hormone aldosterone, the mineralocorticoid receptor increases the number and activity of these proteins at the cell membrane of certain kidney cells. One of these proteins is ENaC, which transports sodium into the cell; another protein simultaneously transports sodium out of the cell and potassium into the cell. These proteins help keep sodium in the body through a process called reabsorption and remove potassium from the body through a process called secretion. Mutations in the NR3C2 gene lead to a nonfunctional or abnormally functioning mineralocorticoid receptor protein that cannot properly regulate the specialized proteins that transport sodium and potassium. As a result, sodium reabsorption and potassium secretion are both decreased, causing hyponatremia and hyperkalemia. Mutations in the SCNN1A, SCNN1B, and SCNN1G genes result in reduced functioning or nonfunctioning ENaC channels. As in autosomal dominant PHA1, the reduction or absence of ENaC function in the kidneys leads to hyponatremia and hyperkalemia. In addition, nonfunctional ENaC channels in other body systems lead to additional signs and symptoms of autosomal recessive PHA1, including lung infections and skin lesions. | pseudohypoaldosteronism type 1 |
Is pseudohypoaldosteronism type 1 inherited ? | PHA1 can have different inheritance patterns. When the condition is caused by mutations in the NR3C2 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. When PHA1 is caused by mutations in the SCNN1A, SCNN1B, or SCNN1G genes, 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. | pseudohypoaldosteronism type 1 |
What are the treatments for pseudohypoaldosteronism type 1 ? | These resources address the diagnosis or management of pseudohypoaldosteronism type 1: - Genetic Testing Registry: Pseudohypoaldosteronism type 1 autosomal dominant - Genetic Testing Registry: Pseudohypoaldosteronism type 1 autosomal recessive - MedlinePlus Encyclopedia: Hyponatremia - University of Maryland Medical Center: Hyperkalemia 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 | pseudohypoaldosteronism type 1 |
What is (are) autosomal recessive congenital stationary night blindness ? | Autosomal recessive congenital stationary night blindness is a disorder of the retina, which is the specialized tissue at the back of the eye that detects light and color. People with this condition typically have difficulty seeing and distinguishing objects in low light (night blindness). For example, they may not be able to identify road signs at night or see stars in the night sky. They also often have other vision problems, including loss of sharpness (reduced acuity), nearsightedness (myopia), involuntary movements of the eyes (nystagmus), and eyes that do not look in the same direction (strabismus). The vision problems associated with this condition are congenital, which means they are present from birth. They tend to remain stable (stationary) over time. | autosomal recessive congenital stationary night blindness |
How many people are affected by autosomal recessive congenital stationary night blindness ? | Autosomal recessive congenital stationary night blindness is likely a rare disease; however, its prevalence is unknown. | autosomal recessive congenital stationary night blindness |
What are the genetic changes related to autosomal recessive congenital stationary night blindness ? | Mutations in several genes can cause autosomal recessive congenital stationary night blindness. Each of these genes provide instructions for making proteins that are found in the retina. These proteins are involved in sending (transmitting) visual signals from cells called rods, which are specialized for vision in low light, to cells called bipolar cells, which relay the signals to other retinal cells. This signaling is an essential step in the transmission of visual information from the eyes to the brain. Mutations in two genes, GRM6 and TRPM1, cause most cases of this condition. These genes provide instructions for making proteins that are necessary for bipolar cells to receive and relay signals. Mutations in other genes involved in the same bipolar cell signaling pathway are likely responsible for a small percentage of cases of autosomal recessive congenital stationary night blindness. Gene mutations that cause autosomal recessive congenital stationary night blindness disrupt the transmission of visual signals between rod cells and bipolar cells or interfere with the bipolar cells' ability to pass on these signals. As a result, visual information received by rod cells cannot be effectively transmitted to the brain, leading to difficulty seeing in low light. The cause of the other vision problems associated with this condition is unclear. It has been suggested that the mechanisms that underlie night blindness can interfere with other visual systems, causing myopia, reduced visual acuity, and other impairments. Some people with autosomal recessive congenital stationary night blindness have no identified mutation in any of the known genes. The cause of the disorder in these individuals is unknown. | autosomal recessive congenital stationary night blindness |
Is autosomal recessive congenital stationary night blindness 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. | autosomal recessive congenital stationary night blindness |
What are the treatments for autosomal recessive congenital stationary night blindness ? | These resources address the diagnosis or management of autosomal recessive congenital stationary night blindness: - Genetic Testing Registry: Congenital stationary night blindness, type 1B - Genetic Testing Registry: Congenital stationary night blindness, type 1C - Genetic Testing Registry: Congenital stationary night blindness, type 1D - Genetic Testing Registry: Congenital stationary night blindness, type 1E - Genetic Testing Registry: Congenital stationary night blindness, type 1F - Genetic Testing Registry: Congenital stationary night blindness, type 2B 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 | autosomal recessive congenital stationary night blindness |
What is (are) craniometaphyseal dysplasia ? | Craniometaphyseal dysplasia is a rare condition characterized by progressive thickening of bones in the skull (cranium) and abnormalities at the ends of long bones in the limbs (metaphyseal dysplasia). Except in the most severe cases, the lifespan of people with craniometaphyseal dysplasia is normal. Bone overgrowth in the head causes many of the signs and symptoms of craniometaphyseal dysplasia. Affected individuals typically have distinctive facial features such as a wide nasal bridge, a prominent forehead, wide-set eyes (hypertelorism), and a prominent jaw. Excessive new bone formation (hyperostosis) in the jaw can delay teething (dentition) or result in absent (non-erupting) teeth. Infants with this condition may have breathing or feeding problems caused by narrow nasal passages. In severe cases, abnormal bone growth can compress the nerves that emerge from the brain and extend to various areas of the head and neck (cranial nerves). Compression of the cranial nerves can lead to paralyzed facial muscles (facial nerve palsy), blindness, or deafness. The x-rays of individuals with craniometaphyseal dysplasia show unusually shaped long bones, particularly the large bones in the legs. The ends of these bones (metaphyses) are wider and appear less dense in people with this condition. There are two types of craniometaphyseal dysplasia, which are distinguished by their pattern of inheritance. They are known as the autosomal dominant and autosomal recessive types. Autosomal recessive craniometaphyseal dysplasia is typically more severe than the autosomal dominant form. | craniometaphyseal dysplasia |
How many people are affected by craniometaphyseal dysplasia ? | Craniometaphyseal dysplasia is a very rare disorder; its incidence is unknown. | craniometaphyseal dysplasia |
What are the genetic changes related to craniometaphyseal dysplasia ? | Mutations in the ANKH gene cause autosomal dominant craniometaphyseal dysplasia. The ANKH gene provides instructions for making a protein that is present in bone and transports a molecule called pyrophosphate out of cells. Pyrophosphate helps regulate bone formation by preventing mineralization, the process by which minerals such as calcium and phosphorus are deposited in developing bones. The ANKH protein may have other, unknown functions. Mutations in the ANKH gene that cause autosomal dominant craniometaphyseal dysplasia may decrease the ANKH protein's ability to transport pyrophosphate out of cells. Reduced levels of pyrophosphate can increase bone mineralization, contributing to the bone overgrowth seen in craniometaphyseal dysplasia. Why long bones are shaped differently and only the skull bones become thicker in people with this condition remains unclear. The genetic cause of autosomal recessive craniometaphyseal dysplasia is unknown. Researchers believe that mutations in an unidentified gene on chromosome 6 may be responsible for the autosomal recessive form of this condition. | craniometaphyseal dysplasia |
Is craniometaphyseal dysplasia inherited ? | Craniometaphyseal dysplasia can have different inheritance patterns. In most cases this condition is inherited in an autosomal dominant pattern, which means one altered copy of the ANKH gene in each cell is sufficient to cause the disorder. Individuals with autosomal dominant craniometaphyseal dysplasia typically have one parent who also has the condition. Less often, cases result from new mutations in the gene and occur in people with no history of the disorder in their family. Rarely, craniometaphyseal dysplasia is suspected to have autosomal recessive inheritance when unaffected parents have more than one child with the condition. Autosomal recessive disorders are caused by mutations in both copies of a gene in each cell. The parents of an individual with an autosomal recessive condition each carry one copy of a mutated gene, but they typically do not show signs and symptoms of the disorder. | craniometaphyseal dysplasia |
What are the treatments for craniometaphyseal dysplasia ? | These resources address the diagnosis or management of craniometaphyseal dysplasia: - Gene Review: Gene Review: Craniometaphyseal Dysplasia, Autosomal Dominant - Genetic Testing Registry: Craniometaphyseal dysplasia, autosomal dominant - Genetic Testing Registry: Craniometaphyseal dysplasia, autosomal recessive type - MedlinePlus Encyclopedia: Facial Paralysis 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 | craniometaphyseal dysplasia |
What is (are) atelosteogenesis type 3 ? | Atelosteogenesis type 3 is a disorder that affects the development of bones throughout the body. Affected individuals are born with inward- and upward-turning feet (clubfeet) and dislocations of the hips, knees, and elbows. Bones in the spine, rib cage, pelvis, and limbs may be underdeveloped or in some cases absent. As a result of the limb bone abnormalities, individuals with this condition have very short arms and legs. Their hands and feet are wide, with broad fingers and toes that may be permanently bent (camptodactyly) or fused together (syndactyly). Characteristic facial features include a broad forehead, wide-set eyes (hypertelorism), and an underdeveloped nose. About half of affected individuals have an opening in the roof of the mouth (a cleft palate.) Individuals with atelosteogenesis type 3 typically have an underdeveloped rib cage that affects the development and functioning of the lungs. As a result, affected individuals are usually stillborn or die shortly after birth from respiratory failure. Some affected individuals survive longer, usually with intensive medical support. They typically experience further respiratory problems as a result of weakness of the airways that can lead to partial closing, short pauses in breathing (apnea), or frequent infections. People with atelosteogenesis type 3 who survive past the newborn period may have learning disabilities and delayed language skills, which are probably caused by low levels of oxygen in the brain due to respiratory problems. As a result of their orthopedic abnormalities, they also have delayed development of motor skills such as standing and walking. | atelosteogenesis type 3 |
How many people are affected by atelosteogenesis type 3 ? | Atelosteogenesis type 3 is a rare disorder; its exact prevalence is unknown. About two dozen affected individuals have been identified. | atelosteogenesis type 3 |
What are the genetic changes related to atelosteogenesis type 3 ? | Mutations in the FLNB gene cause atelosteogenesis type 3. The FLNB gene provides instructions for making a protein called filamin B. This protein helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Filamin B attaches (binds) to another protein called actin and helps the actin to form the branching network of filaments that makes up the cytoskeleton. It also links actin to many other proteins to perform various functions within the cell, including the cell signaling that helps determine how the cytoskeleton will change as tissues grow and take shape during development. Filamin B is especially important in the development of the skeleton before birth. It is active (expressed) in the cell membranes of cartilage-forming cells (chondrocytes). Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone (a process called ossification), except for the cartilage that continues to cover and protect the ends of bones and is present in the nose, airways (trachea and bronchi), and external ears. Filamin B appears to be important for normal cell growth and division (proliferation) and maturation (differentiation) of chondrocytes and for the ossification of cartilage. FLNB gene mutations that cause atelosteogenesis type 3 change single protein building blocks (amino acids) in the filamin B protein or delete a small section of the protein sequence, resulting in an abnormal protein. This abnormal protein appears to have a new, atypical function that interferes with the proliferation or differentiation of chondrocytes, impairing ossification and leading to the signs and symptoms of atelosteogenesis type 3. | atelosteogenesis type 3 |
Is atelosteogenesis type 3 inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most cases result from new mutations in the gene and occur in people with no history of the disorder in their family. | atelosteogenesis type 3 |
What are the treatments for atelosteogenesis type 3 ? | These resources address the diagnosis or management of atelosteogenesis type 3: - Gene Review: Gene Review: FLNB-Related Disorders - Genetic Testing Registry: Atelosteogenesis type 3 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | atelosteogenesis type 3 |
What is (are) hereditary sensory and autonomic neuropathy type V ? | Hereditary sensory and autonomic neuropathy type V (HSAN5) is a condition that primarily affects the sensory nerve cells (sensory neurons), which transmit information about sensations such as pain, temperature, and touch. These sensations are impaired in people with HSAN5. The signs and symptoms of HSAN5 appear early, usually at birth or during infancy. People with HSAN5 lose the ability to feel pain, heat, and cold. Deep pain perception, the feeling of pain from injuries to bones, ligaments, or muscles, is especially affected in people with HSAN5. Because of the inability to feel deep pain, affected individuals suffer repeated severe injuries such as bone fractures and joint injuries that go unnoticed. Repeated trauma can lead to a condition called Charcot joints, in which the bones and tissue surrounding joints are destroyed. | hereditary sensory and autonomic neuropathy type V |
How many people are affected by hereditary sensory and autonomic neuropathy type V ? | HSAN5 is very rare. Only a few people with the condition have been identified. | hereditary sensory and autonomic neuropathy type V |
What are the genetic changes related to hereditary sensory and autonomic neuropathy type V ? | Mutations in the NGF gene cause HSAN5. The NGF gene provides instructions for making a protein called nerve growth factor beta (NGF) that is important in the development and survival of nerve cells (neurons), including sensory neurons. The NGF protein functions by attaching (binding) to its receptors, which are found on the surface of neurons. Binding of the NGF protein to its receptor transmits signals to the cell to grow and to mature and take on specialized functions (differentiate). This binding also blocks signals in the cell that initiate the process of self-destruction (apoptosis). Additionally, NGF signaling plays a role in pain sensation. Mutation of the NGF gene leads to the production of a protein that cannot bind to the receptor and does not transmit signals properly. Without the proper signaling, sensory neurons die and pain sensation is altered, resulting in the inability of people with HSAN5 to feel pain. | hereditary sensory and autonomic neuropathy type V |
Is hereditary sensory and autonomic neuropathy type V inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | hereditary sensory and autonomic neuropathy type V |
What are the treatments for hereditary sensory and autonomic neuropathy type V ? | These resources address the diagnosis or management of HSAN5: - Genetic Testing Registry: Congenital sensory neuropathy with selective loss of small myelinated fibers These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | hereditary sensory and autonomic neuropathy type V |
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