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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. | Tourette syndrome |
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. | Tourette syndrome |
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. | 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. | Tourette syndrome |
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 | Tourette syndrome |
What is (are) Buschke-Ollendorff syndrome ? | Buschke-Ollendorff syndrome is a hereditary disorder of connective tissues, which are tissues that provide strength and flexibility to structures throughout the body. Specifically, the condition is characterized by skin growths called connective tissue nevi and a bone abnormality known as osteopoikilosis. Connective tissue nevi are small, noncancerous lumps on the skin. They tend to appear in childhood and are widespread in people with Buschke-Ollendorff syndrome. The most common form of these nevi are elastomas, which are made up of a type of stretchy connective tissue called elastic fibers. Less commonly, affected individuals have nevi called collagenomas, which are made up of another type of connective tissue called collagen. Osteopoikilosis, which is from the Greek words for "spotted bones," is a skeletal abnormality characterized by small, round areas of increased bone density that appear as brighter spots on x-rays. Osteopoikilosis usually occurs near the ends of the long bones of the arms and legs, and in the bones of the hands, feet, and pelvis. The areas of increased bone density appear during childhood. They do not cause pain or other health problems. | Buschke-Ollendorff syndrome |
How many people are affected by Buschke-Ollendorff syndrome ? | Buschke-Ollendorff syndrome has an estimated incidence of 1 in 20,000 people worldwide. | Buschke-Ollendorff syndrome |
What are the genetic changes related to Buschke-Ollendorff syndrome ? | Buschke-Ollendorff syndrome results from mutations in the LEMD3 gene. This gene provides instructions for making a protein that helps control signaling through two chemical pathways known as the bone morphogenic protein (BMP) and transforming growth factor-beta (TGF-) pathways. These signaling pathways regulate various cellular processes and are involved in the growth of cells, including new bone cells. Mutations in the LEMD3 gene reduce the amount of functional LEMD3 protein that is produced. A shortage of this protein prevents it from controlling BMP and TGF- signaling effectively, leading to increased signaling through both of these pathways. Studies suggest that the enhanced signaling increases the formation of bone tissue, resulting in areas of overly dense bone. It is unclear how it is related to the development of connective tissue nevi in people with Buschke-Ollendorff syndrome. | Buschke-Ollendorff syndrome |
Is Buschke-Ollendorff 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 many cases, an affected person has a parent and other family members with the condition. While most people with Buschke-Ollendorff syndrome have both connective tissue nevi and osteopoikilosis, some affected families include individuals who have the skin abnormalities alone or the bone abnormalities alone. When osteopoikilosis occurs without connective tissue nevi, the condition is often called isolated osteopoikilosis. | Buschke-Ollendorff syndrome |
What are the treatments for Buschke-Ollendorff syndrome ? | These resources address the diagnosis or management of Buschke-Ollendorff syndrome: - Genetic Testing Registry: Dermatofibrosis lenticularis disseminata 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 | Buschke-Ollendorff syndrome |
What is (are) paramyotonia congenita ? | Paramyotonia congenita is a disorder that affects muscles used for movement (skeletal muscles). Beginning in infancy or early childhood, people with this condition experience bouts of sustained muscle tensing (myotonia) that prevent muscles from relaxing normally. Myotonia causes muscle stiffness that typically appears after exercise and can be induced by muscle cooling. This stiffness chiefly affects muscles in the face, neck, arms, and hands, although it can also affect muscles used for breathing and muscles in the lower body. Unlike many other forms of myotonia, the muscle stiffness associated with paramyotonia congenita tends to worsen with repeated movements. Most peopleeven those without muscle diseasefeel that their muscles do not work as well when they are cold. This effect is dramatic in people with paramyotonia congenita. Exposure to cold initially causes muscle stiffness in these individuals, and prolonged cold exposure leads to temporary episodes of mild to severe muscle weakness that may last for several hours at a time. Some older people with paramyotonia congenita develop permanent muscle weakness that can be disabling. | paramyotonia congenita |
How many people are affected by paramyotonia congenita ? | Paramyotonia congenita is an uncommon disorder; it is estimated to affect fewer than 1 in 100,000 people. | paramyotonia congenita |
What are the genetic changes related to paramyotonia congenita ? | Mutations in the SCN4A gene cause paramyotonia congenita. This gene provides instructions for making a protein that is critical for the normal function of skeletal muscle cells. For the body to move normally, skeletal muscles must tense (contract) and relax in a coordinated way. Muscle contractions are triggered by the flow of positively charged atoms (ions), including sodium, into skeletal muscle cells. The SCN4A protein forms channels that control the flow of sodium ions into these cells. Mutations in the SCN4A gene alter the usual structure and function of sodium channels. The altered channels cannot effectively regulate the flow of sodium ions into skeletal muscle cells. The resulting increase in ion flow interferes with normal muscle contraction and relaxation, leading to episodes of muscle stiffness and weakness. | paramyotonia congenita |
Is paramyotonia congenita 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 many cases, an affected person has one parent with the condition. | paramyotonia congenita |
What are the treatments for paramyotonia congenita ? | These resources address the diagnosis or management of paramyotonia congenita: - Genetic Testing Registry: Paramyotonia congenita of von Eulenburg - Periodic Paralysis International: How is Periodic Paralysis Diagnosed? 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 | paramyotonia congenita |
What is (are) cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy ? | Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, usually called CADASIL, is an inherited condition that causes stroke and other impairments. This condition affects blood flow in small blood vessels, particularly cerebral vessels within the brain. The muscle cells surrounding these blood vessels (vascular smooth muscle cells) are abnormal and gradually die. In the brain, the resulting blood vessel damage (arteriopathy) can cause migraines, often with visual sensations or auras, or recurrent seizures (epilepsy). Damaged blood vessels reduce blood flow and can cause areas of tissue death (infarcts) throughout the body. An infarct in the brain can lead to a stroke. In individuals with CADASIL, a stroke can occur at any time from childhood to late adulthood, but typically happens during mid-adulthood. People with CADASIL often have more than one stroke in their lifetime. Recurrent strokes can damage the brain over time. Strokes that occur in the subcortical region of the brain, which is involved in reasoning and memory, can cause progressive loss of intellectual function (dementia) and changes in mood and personality. Many people with CADASIL also develop leukoencephalopathy, which is a change in a type of brain tissue called white matter that can be seen with magnetic resonance imaging (MRI). The age at which the signs and symptoms of CADASIL first begin varies greatly among affected individuals, as does the severity of these features. CADASIL is not associated with the common risk factors for stroke and heart attack, such as high blood pressure and high cholesterol, although some affected individuals might also have these health problems. | cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy |
How many people are affected by cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy ? | CADASIL is likely a rare condition; however, its prevalence is unknown. | cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy |
What are the genetic changes related to cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy ? | Mutations in the NOTCH3 gene cause CADASIL. The NOTCH3 gene provides instructions for producing the Notch3 receptor protein, which is important for the normal function and survival of vascular smooth muscle cells. When certain molecules attach (bind) to Notch3 receptors, the receptors send signals to the nucleus of the cell. These signals then turn on (activate) particular genes within vascular smooth muscle cells. NOTCH3 gene mutations lead to the production of an abnormal Notch3 receptor protein that impairs the function and survival of vascular smooth muscle cells. Disruption of Notch3 functioning can lead to the self-destruction (apoptosis) of these cells. In the brain, the loss of vascular smooth muscle cells results in blood vessel damage that can cause the signs and symptoms of CADASIL. | cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy |
Is cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered NOTCH3 gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the mutation from one affected parent. A few rare cases may result from new mutations in the NOTCH3 gene. These cases occur in people with no history of the disorder in their family. | cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy |
What are the treatments for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy ? | These resources address the diagnosis or management of CADASIL: - Butler Hospital: Treatment and Management of CADASIL - Gene Review: Gene Review: CADASIL - Genetic Testing Registry: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy - MedlinePlus Encyclopedia: Multi-Infarct 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 | cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy |
What is (are) dihydropyrimidine dehydrogenase deficiency ? | Dihydropyrimidine dehydrogenase deficiency is a disorder characterized by a wide range of severity, with neurological problems in some individuals and no signs or symptoms in others. In people with severe dihydropyrimidine dehydrogenase deficiency, the disorder becomes apparent in infancy. These affected individuals have neurological problems such as recurrent seizures (epilepsy), intellectual disability, a small head size (microcephaly), increased muscle tone (hypertonia), delayed development of motor skills such as walking, and autistic behaviors that affect communication and social interaction. Other affected individuals are asymptomatic, which means they do not have any signs or symptoms of the condition. Individuals with asymptomatic dihydropyrimidine dehydrogenase deficiency may be identified only by laboratory testing. People with dihydropyrimidine dehydrogenase deficiency, including those who otherwise exhibit no symptoms, are vulnerable to severe, potentially life-threatening toxic reactions to certain drugs called fluoropyrimidines that are used to treat cancer. Common examples of these drugs are 5-fluorouracil and capecitabine. These drugs are not broken down efficiently by people with dihydropyrimidine dehydrogenase deficiency and build up to toxic levels in the body (fluoropyrimidine toxicity). Severe inflammation and ulceration of the lining of the gastrointestinal tract (mucositis) may occur, which can lead to signs and symptoms including mouth sores, abdominal pain, bleeding, nausea, vomiting, and diarrhea. Fluoropyrimidine toxicity may also lead to low numbers of white blood cells (neutropenia), which increases the risk of infections. It can also be associated with low numbers of platelets in the blood (thrombocytopenia), which impairs blood clotting and may lead to abnormal bleeding (hemorrhage). Redness, swelling, numbness, and peeling of the skin on the palms and soles (hand-foot syndrome); shortness of breath; and hair loss may also occur. | dihydropyrimidine dehydrogenase deficiency |
How many people are affected by dihydropyrimidine dehydrogenase deficiency ? | Severe dihydropyrimidine dehydrogenase deficiency, with its early-onset neurological symptoms, is a rare disorder. Its prevalence is unknown. However, between 2 and 8 percent of the general population may be vulnerable to toxic reactions to fluoropyrimidine drugs caused by otherwise asymptomatic dihydropyrimidine dehydrogenase deficiency. | dihydropyrimidine dehydrogenase deficiency |
What are the genetic changes related to dihydropyrimidine dehydrogenase deficiency ? | Dihydropyrimidine dehydrogenase deficiency is caused by mutations in the DPYD gene. This gene provides instructions for making an enzyme called dihydropyrimidine dehydrogenase, which is involved in the breakdown of molecules called uracil and thymine. Uracil and thymine are pyrimidines, which are one type of nucleotide. Nucleotides are building blocks of DNA, its chemical cousin RNA, and molecules such as ATP and GTP that serve as energy sources in the cell. Mutations in the DPYD gene result in a lack (deficiency) of functional dihydropyrimidine dehydrogenase. Dihydropyrimidine dehydrogenase deficiency interferes with the breakdown of uracil and thymine, and results in excess quantities of these molecules in the blood, urine, and the fluid that surrounds the brain and spinal cord (cerebrospinal fluid). It is unclear how the excess uracil and thymine are related to the specific signs and symptoms of dihydropyrimidine dehydrogenase deficiency. Mutations that result in the absence (complete deficiency) of dihydropyrimidine dehydrogenase generally lead to more severe signs and symptoms than do mutations that lead to a partial deficiency of this enzyme. Because fluoropyrimidine drugs are also broken down by the dihydropyrimidine dehydrogenase enzyme, deficiency of this enzyme leads to the drug buildup that causes fluoropyrimidine toxicity. | dihydropyrimidine dehydrogenase deficiency |
Is dihydropyrimidine dehydrogenase deficiency inherited ? | Dihydropyrimidine dehydrogenase deficiency is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Depending on the severity of these mutations, people with two mutated copies of the DPYD gene in each cell may exhibit the signs and symptoms of this disorder, or they may be generally asymptomatic but at risk for toxic reactions to fluoropyrimidine drugs. 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. However, people with one mutated copy of the DPYD gene in each cell may still experience toxic reactions to fluoropyrimidine drugs. | dihydropyrimidine dehydrogenase deficiency |
What are the treatments for dihydropyrimidine dehydrogenase deficiency ? | These resources address the diagnosis or management of dihydropyrimidine dehydrogenase deficiency: - Genetic Testing Registry: Dihydropyrimidine dehydrogenase deficiency These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | dihydropyrimidine dehydrogenase deficiency |
What is (are) acromicric dysplasia ? | Acromicric dysplasia is a condition characterized by severely short stature, short limbs, stiff joints, and distinctive facial features. Newborns with acromicric dysplasia are of normal size, but slow growth over time results in short stature. The average height of adults with this disorder is about 4 feet, 2 inches for women and 4 feet, 5 inches for men. The long bones of the arms and legs, and the bones in the hands and feet, are shorter than would be expected for the individual's height. Other skeletal features that occur in this disorder include slowed mineralization of bone (delayed bone age), abnormally shaped bones of the spine (vertebrae), and constrained movement of joints. Affected individuals often develop carpal tunnel syndrome, which is characterized by numbness, tingling, and weakness in the hands and fingers. A misalignment of the hip joints (hip dysplasia) can also occur in this disorder. These skeletal and joint problems may require treatment, but most affected individuals have few limitations in their activities. Children with acromicric dysplasia may have a round face, sharply defined eyebrows, long eyelashes, a bulbous nose with upturned nostrils, a long space between the nose and upper lip (philtrum), and a small mouth with thick lips. These facial differences become less apparent in adulthood. Intelligence is unaffected in this disorder, and life expectancy is generally normal. | acromicric dysplasia |
How many people are affected by acromicric dysplasia ? | Acromicric dysplasia is a rare disorder; its prevalence is unknown. | acromicric dysplasia |
What are the genetic changes related to acromicric dysplasia ? | Acromicric dysplasia is caused by mutations in the FBN1 gene, which provides instructions for making a large protein called fibrillin-1. This protein is transported out of cells into the extracellular matrix, which is an intricate lattice of proteins and other molecules that forms in the spaces between cells. In this matrix, molecules of fibrillin-1 attach (bind) to each other and to other proteins to form threadlike filaments called microfibrils. The microfibrils become part of the fibers that provide strength and flexibility to connective tissues, which support the bones, skin, and other tissues and organs. Additionally, microfibrils store molecules called growth factors, including transforming growth factor beta (TGF-), and release them at various times to control the growth and repair of tissues and organs throughout the body. Most of the FBN1 gene mutations that cause acromicric dysplasia change single protein building blocks in the fibrillin-1 protein. The mutations result in a reduction and disorganization of the microfibrils. Without enough normal microfibrils to store TGF-, the growth factor is abnormally active. These effects likely contribute to the physical abnormalities that occur in acromicric dysplasia, but the mechanisms are unclear. | acromicric dysplasia |
Is acromicric dysplasia inherited ? | Acromicric dysplasia is an autosomal dominant condition, 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. In other cases, an affected person inherits the mutation from one affected parent. | acromicric dysplasia |
What are the treatments for acromicric dysplasia ? | These resources address the diagnosis or management of acromicric dysplasia: - Genetic Testing Registry: Acromicric 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 | acromicric dysplasia |
What is (are) cranioectodermal dysplasia ? | Cranioectodermal dysplasia is a disorder that affects many parts of the body. The most common features involve bone abnormalities and abnormal development of certain tissues known as ectodermal tissues, which include the skin, hair, nails, and teeth. The signs and symptoms of this condition vary among affected individuals, even among members of the same family. Distinctive abnormalities of the skull and face are common in people with cranioectodermal dysplasia. Most affected individuals have a prominent forehead (frontal bossing) and an elongated head (dolichocephaly) due to abnormal fusion of certain skull bones (sagittal craniosynostosis). A variety of facial abnormalities can occur in people with this condition; these include low-set ears that may also be rotated backward, an increased distance between the inner corners of the eyes (telecanthus), and outside corners of the eyes that point upward or downward (upslanting or downslanting palpebral fissures) among others. Development of bones in the rest of the skeleton is also affected in this condition. Abnormalities in the long bones of the arms and legs (metaphyseal dysplasia) lead to short limbs and short stature. In addition, affected individuals often have short fingers (brachydactyly). Some people with this condition have short rib bones and a narrow rib cage, which can cause breathing problems, especially in affected newborns. Abnormal development of ectodermal tissues in people with cranioectodermal dysplasia can lead to sparse hair, small or missing teeth, short fingernails and toenails, and loose skin. Cranioectodermal dysplasia can affect additional organs and tissues in the body. A kidney disorder known as nephronophthisis occurs in many people with this condition, and it can lead to a life-threatening failure of kidney function known as end-stage renal disease. Abnormalities of the liver, heart, or eyes also occur in people with cranioectodermal dysplasia. | cranioectodermal dysplasia |
How many people are affected by cranioectodermal dysplasia ? | Cranioectodermal dysplasia is a rare condition with an unknown prevalence. Approximately 40 cases of this condition have been described in the medical literature. | cranioectodermal dysplasia |
What are the genetic changes related to cranioectodermal dysplasia ? | Cranioectodermal dysplasia is caused by mutations in one of at least four genes: the WDR35, IFT122, WDR19, or IFT43 gene. The protein produced from each of these genes is one piece (subunit) of a protein complex called IFT complex A (IFT-A). This complex is found in finger-like structures called cilia that stick out from the surface of cells. These structures are important for the development and function of many types of cells and tissues. The IFT-A complex is involved in a process called intraflagellar transport, which moves substances within cilia. This movement is essential for the assembly and maintenance of these structures. The IFT-A complex carries materials from the tip to the base of cilia. Mutations in any of the four mentioned genes reduce the amount or function of one of the IFT-A subunits. Shortage or abnormal function of a single component of the IFT-A complex impairs the function of the entire complex, disrupting the assembly and maintenance of cilia. These mutations lead to a smaller number of cilia and to abnormalities in their shape and structure. Although the mechanism is unclear, a loss of normal cilia impedes proper development of bone, ectodermal tissues, and other tissues and organs, leading to the features of cranioectodermal dysplasia. About 40 percent of people with cranioectodermal dysplasia have mutations in one of the four known genes. The cause of the condition in people without mutations in one of these genes is unknown. | cranioectodermal dysplasia |
Is cranioectodermal dysplasia 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. | cranioectodermal dysplasia |
What are the treatments for cranioectodermal dysplasia ? | These resources address the diagnosis or management of cranioectodermal dysplasia: - Gene Review: Gene Review: Cranioectodermal Dysplasia - Genetic Testing Registry: Cranioectodermal dysplasia 1 - Genetic Testing Registry: Cranioectodermal dysplasia 2 - Genetic Testing Registry: Cranioectodermal dysplasia 3 - Genetic Testing Registry: Cranioectodermal dysplasia 4 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 | cranioectodermal dysplasia |
What is (are) short-chain acyl-CoA dehydrogenase deficiency ? | Short-chain acyl-CoA dehydrogenase (SCAD) deficiency is a condition that prevents the body from converting certain fats into energy, especially during periods without food (fasting). Signs and symptoms of SCAD deficiency may appear during infancy or early childhood and can include vomiting, low blood sugar (hypoglycemia), a lack of energy (lethargy), poor feeding, and failure to gain weight and grow at the expected rate (failure to thrive). Other features of this disorder may include poor muscle tone (hypotonia), seizures, developmental delay, and a small head size (microcephaly). The symptoms of SCAD deficiency may be triggered by fasting or illnesses such as viral infections. This disorder is sometimes mistaken for Reye syndrome, a severe condition 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. In some people with SCAD deficiency, signs and symptoms do not appear until adulthood. These individuals are more likely to have problems related to muscle weakness and wasting. The severity of this condition varies widely, even among members of the same family. Some individuals are diagnosed with SCAD deficiency based on laboratory testing but never develop any symptoms of the condition. | short-chain acyl-CoA dehydrogenase deficiency |
How many people are affected by short-chain acyl-CoA dehydrogenase deficiency ? | This disorder is thought to affect approximately 1 in 35,000 to 50,000 newborns. | short-chain acyl-CoA dehydrogenase deficiency |
What are the genetic changes related to short-chain acyl-CoA dehydrogenase deficiency ? | Mutations in the ACADS gene cause SCAD deficiency. This gene provides instructions for making an enzyme called short-chain acyl-CoA dehydrogenase, which is required to break down (metabolize) a group of fats called short-chain fatty acids. 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 ACADS gene lead to a shortage (deficiency) of the SCAD enzyme within cells. Without sufficient amounts of this enzyme, short-chain fatty acids are not metabolized properly. As a result, these fats are not converted into energy, which can lead to the signs and symptoms of this disorder, such as lethargy, hypoglycemia, and muscle weakness. It remains unclear why some people with SCAD deficiency never develop any symptoms. | short-chain acyl-CoA dehydrogenase deficiency |
Is short-chain acyl-CoA dehydrogenase 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. | short-chain acyl-CoA dehydrogenase deficiency |
What are the treatments for short-chain acyl-CoA dehydrogenase deficiency ? | These resources address the diagnosis or management of SCAD deficiency: - Baby's First Test - Gene Review: Gene Review: Short-Chain Acyl-CoA Dehydrogenase Deficiency - Genetic Testing Registry: Deficiency of butyryl-CoA dehydrogenase - MedlinePlus Encyclopedia: Newborn Screening Tests These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | short-chain acyl-CoA dehydrogenase deficiency |
What is (are) Klinefelter syndrome ? | Klinefelter syndrome is a chromosomal condition that affects male physical and cognitive development. Its signs and symptoms vary among affected individuals. Affected individuals typically have small testes that do not produce as much testosterone as usual. Testosterone is the hormone that directs male sexual development before birth and during puberty. A shortage of testosterone can lead to delayed or incomplete puberty, breast enlargement (gynecomastia), reduced facial and body hair, and an inability to have biological children (infertility). Some affected individuals also have genital differences including undescended testes (cryptorchidism), the opening of the urethra on the underside of the penis (hypospadias), or an unusually small penis (micropenis). Older children and adults with Klinefelter syndrome tend to be taller than their peers. Compared with unaffected men, adults with Klinefelter syndrome have an increased risk of developing breast cancer and a chronic inflammatory disease called systemic lupus erythematosus. Their chance of developing these disorders is similar to that of women in the general population. Children with Klinefelter syndrome may have learning disabilities and delayed speech and language development. They tend to be quiet, sensitive, and unassertive, but personality characteristics vary among affected individuals. | Klinefelter syndrome |
How many people are affected by Klinefelter syndrome ? | Klinefelter syndrome affects 1 in 500 to 1,000 newborn males. Most variants of Klinefelter syndrome are much rarer, occurring in 1 in 50,000 or fewer newborns. Researchers suspect that Klinefelter syndrome is underdiagnosed because the condition may not be identified in people with mild signs and symptoms. Additionally, the features of the condition vary and overlap significantly with those of other conditions. | Klinefelter syndrome |
What are the genetic changes related to Klinefelter syndrome ? | Klinefelter syndrome is a condition related to the X and Y chromosomes (the sex chromosomes). People typically have two sex chromosomes in each cell: females have two X chromosomes (46,XX), and males have one X and one Y chromosome (46,XY). Most often, Klinefelter syndrome results from the presence of one extra copy of the X chromosome in each cell (47,XXY). Extra copies of genes on the X chromosome interfere with male sexual development, often preventing the testes from functioning normally and reducing the levels of testosterone. Most people with an extra X chromosome have the features described above, although some have few or no associated signs and symptoms. Some people with features of Klinefelter syndrome have more than one extra sex chromosome in each cell (for example, 48,XXXY or 49,XXXXY). These conditions, which are often called variants of Klinefelter syndrome, tend to cause more severe signs and symptoms than classic Klinefelter syndrome. In addition to affecting male sexual development, variants of Klinefelter syndrome are associated with intellectual disability, distinctive facial features, skeletal abnormalities, poor coordination, and severe problems with speech. As the number of extra sex chromosomes increases, so does the risk of these health problems. Some people with features of Klinefelter syndrome have the extra X chromosome in only some of their cells; in these individuals, the condition is described as mosaic Klinefelter syndrome (46,XY/47,XXY). Individuals with mosaic Klinefelter syndrome may have milder signs and symptoms, depending on how many cells have an additional X chromosome. | Klinefelter syndrome |
Is Klinefelter syndrome inherited ? | Klinefelter syndrome and its variants are not inherited; these chromosomal changes usually occur as random events during the formation of reproductive cells (eggs and sperm) in a parent. An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. For example, an egg or sperm cell may gain one or more extra copies of the X chromosome as a result of nondisjunction. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have one or more extra X chromosomes in each of the body's cells. Mosaic 46,XY/47,XXY is also not inherited. It occurs as a random event during cell division early in fetal development. As a result, some of the body's cells have one X chromosome and one Y chromosome (46,XY), and other cells have an extra copy of the X chromosome (47,XXY). | Klinefelter syndrome |
What are the treatments for Klinefelter syndrome ? | These resources address the diagnosis or management of Klinefelter syndrome: - Genetic Testing Registry: Klinefelter's syndrome, XXY - MedlinePlus Encyclopedia: Klinefelter Syndrome - MedlinePlus Encyclopedia: Testicular Failure 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 | Klinefelter syndrome |
What is (are) fumarase deficiency ? | Fumarase deficiency is a condition that primarily affects the nervous system, especially the brain. Affected infants may have an abnormally small head size (microcephaly), abnormal brain structure, severe developmental delay, weak muscle tone (hypotonia), and failure to gain weight and grow at the expected rate (failure to thrive). They may also experience seizures. Some people with this disorder have unusual facial features, including a prominent forehead (frontal bossing), low-set ears, a small jaw (micrognathia), widely spaced eyes (ocular hypertelorism), and a depressed nasal bridge. An enlarged liver and spleen (hepatosplenomegaly) may also be associated with this disorder, as well as an excess of red blood cells (polycythemia) or deficiency of white blood cells (leukopenia) in infancy. Affected individuals usually survive only a few months, but a few have lived into early adulthood. | fumarase deficiency |
How many people are affected by fumarase deficiency ? | Fumarase deficiency is a very rare disorder. Approximately 100 affected individuals have been reported worldwide. Several were born in an isolated religious community in the southwestern United States. | fumarase deficiency |
What are the genetic changes related to fumarase deficiency ? | The FH gene provides instructions for making an enzyme called fumarase (also known as fumarate hydratase). Fumarase participates in an important series of reactions known as the citric acid cycle or Krebs cycle, which allows cells to use oxygen and generate energy. Specifically, fumarase helps convert a molecule called fumarate to a molecule called malate. Mutations in the FH gene disrupt the enzyme's ability to help convert fumarate to malate, interfering with the function of this reaction in the citric acid cycle. Impairment of the process that generates energy for cells is particularly harmful to cells in the developing brain, and this impairment results in the signs and symptoms of fumarase deficiency. | fumarase deficiency |
Is fumarase 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. | fumarase deficiency |
What are the treatments for fumarase deficiency ? | These resources address the diagnosis or management of fumarase deficiency: - Gene Review: Gene Review: Fumarate Hydratase Deficiency - Genetic Testing Registry: Fumarase deficiency These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | fumarase deficiency |
What is (are) phosphoglycerate dehydrogenase deficiency ? | Phosphoglycerate dehydrogenase deficiency is a condition characterized by an unusually small head size (microcephaly); impaired development of physical reactions, movements, and speech (psychomotor retardation); and recurrent seizures (epilepsy). Different types of phosphoglycerate dehydrogenase deficiency have been described; they are distinguished by their severity and the age at which symptoms first begin. Most affected individuals have the infantile form, which is the most severe form, and are affected from infancy. Symptoms of the juvenile and adult types appear later in life; these types are very rare. In phosphoglycerate dehydrogenase deficiency there is a progressive loss of brain cells leading to a loss of brain tissue (brain atrophy), specifically affecting the fatty tissue known as myelin that surrounds nerve cells (hypomyelination). Frequently, the tissue that connects the two halves of the brain (corpus callosum) is small and thin, and the fluid-filled cavities (ventricles) near the center of the brain are enlarged. Because development of the brain is disrupted, the head does not grow at the same rate as the body, so it appears that the head is getting smaller as the body grows (progressive microcephaly). Poor brain growth leads to an inability to achieve many developmental milestones such as sitting unsupported and speaking. Many affected infants also have difficulty feeding. The seizures in phosphoglycerate dehydrogenase deficiency can vary in type. Recurrent muscle contractions called infantile spasms are typical early in the disorder. Without early treatment, seizures may progress to tonic-clonic seizures, which involve a loss of consciousness, muscle rigidity, and convulsions; myoclonic seizures, which involve rapid, uncontrolled muscle jerks; or drop attacks, which are sudden episodes of weak muscle tone. Individuals with the infantile form of phosphoglycerate dehydrogenase deficiency develop many of the features described above. Individuals with the juvenile form typically have epilepsy as well as mild developmental delay and intellectual disability. Only one case of the adult form has been reported; signs and symptoms began in mid-adulthood and included mild intellectual disability; difficulty coordinating movements (ataxia); and numbness, tingling, and pain in the arms and legs (sensory neuropathy). | phosphoglycerate dehydrogenase deficiency |
How many people are affected by phosphoglycerate dehydrogenase deficiency ? | This condition is likely a rare disorder, but its prevalence is unknown. At least 15 cases have been described in the scientific literature. | phosphoglycerate dehydrogenase deficiency |
What are the genetic changes related to phosphoglycerate dehydrogenase deficiency ? | Mutations in the PHGDH gene cause phosphoglycerate dehydrogenase deficiency. The PHGDH gene provides instructions for making the parts (subunits) that make up the phosphoglycerate dehydrogenase enzyme. Four PHGDH subunits combine to form the enzyme. This enzyme is involved in the production of the protein building block (amino acid) serine. Specifically, the enzyme converts a substance called 3-phosphoglycerate to 3-phosphohydroxypyruvate in the first step in serine production. Serine is necessary for the development and function of the brain and spinal cord (central nervous system). Serine is a part of chemical messengers called neurotransmitters that transmit signals in the nervous system. Proteins that form cell membranes and myelin also contain serine. Serine can be obtained from the diet, but brain cells must produce their own serine because dietary serine cannot cross the protective barrier that allows only certain substances to pass between blood vessels and the brain (the blood-brain barrier). PHGDH gene mutations result in the production of an enzyme with decreased function. As a result, less 3-phosphoglycerate is converted into 3-phosphohydroxypyruvate than normal and serine production is stalled at the first step. The lack of serine likely prevents the production of proteins and neurotransmitters in the brain and impairs the formation of normal cells and myelin. These disruptions in normal brain development lead to the signs and symptoms of phosphoglycerate dehydrogenase deficiency. | phosphoglycerate dehydrogenase deficiency |
Is phosphoglycerate dehydrogenase 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. | phosphoglycerate dehydrogenase deficiency |
What are the treatments for phosphoglycerate dehydrogenase deficiency ? | These resources address the diagnosis or management of phosphoglycerate dehydrogenase deficiency: - Genetic Testing Registry: Phosphoglycerate dehydrogenase deficiency - Seattle Children's Hospital: Epilepsy Symptoms and Diagnosis 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 | phosphoglycerate dehydrogenase deficiency |
What is (are) sitosterolemia ? | Sitosterolemia is a condition in which fatty substances (lipids) from vegetable oils, nuts, and other plant-based foods accumulate in the blood and tissues. These lipids are called plant sterols (or phytosterols). Sitosterol is one of several plant sterols that accumulate in this disorder, with a blood level 30 to 100 times greater than normal. Cholesterol, a similar fatty substance found in animal products, is mildly to moderately elevated in many people with sitosterolemia. Cholesterol levels are particularly high in some affected children. Plant sterols are not produced by the body; they are taken in as components of foods. Signs and symptoms of sitosterolemia begin to appear early in life after foods containing plant sterols are introduced into the diet. An accumulation of fatty deposits on the artery walls (atherosclerosis) may occur by adolescence or early adulthood in people with sitosterolemia. The deposits narrow the arteries and can eventually block blood flow, increasing the chance of a heart attack, stroke, or sudden death. People with sitosterolemia typically develop small yellowish growths called xanthomas beginning in childhood. The xanthomas consist of accumulated lipids and may be located anywhere on or just under the skin, typically on the heels, knees, elbows, and buttocks. They may also occur in the bands that connect muscles to bones (tendons), including tendons of the hand and the tendon that connects the heel of the foot to the calf muscles (the Achilles tendon). Large xanthomas can cause pain, difficulty with movement, and cosmetic problems. Joint stiffness and pain resulting from plant sterol deposits may also occur in individuals with sitosterolemia. Less often, affected individuals have blood abnormalities. Occasionally the blood abnormalities are the only signs of the disorder. The red blood cells may be broken down (undergo hemolysis) prematurely, resulting in a shortage of red blood cells (anemia). This type of anemia is called hemolytic anemia. Affected individuals sometimes have abnormally shaped red blood cells called stomatocytes. In addition, the blood cells involved in clotting, called platelets or thrombocytes, may be abnormally large (macrothrombocytopenia). | sitosterolemia |
How many people are affected by sitosterolemia ? | Only 80 to 100 individuals with sitosterolemia have been described in the medical literature. However, researchers believe that this condition is likely underdiagnosed because mild cases often do not come to medical attention. Studies suggest that the prevalence may be at least 1 in 50,000 people. | sitosterolemia |
What are the genetic changes related to sitosterolemia ? | Sitosterolemia is caused by mutations in the ABCG5 or ABCG8 gene. These genes provide instructions for making the two halves of a protein called sterolin. This protein is involved in eliminating plant sterols, which cannot be used by human cells. Sterolin is a transporter protein, which is a type of protein that moves substances across cell membranes. It is found mostly in cells of the intestines and liver. After plant sterols in food are taken into intestinal cells, the sterolin transporters in these cells pump them back into the intestinal tract, decreasing absorption. Sterolin transporters in liver cells pump the plant sterols into a fluid called bile that is released into the intestine. From the intestine, the plant sterols are eliminated with the feces. This process removes most of the dietary plant sterols, and allows only about 5 percent of these substances to get into the bloodstream. Sterolin also helps regulate cholesterol levels in a similar fashion; normally about 50 percent of cholesterol in the diet is absorbed by the body. Mutations in the ABCG5 or ABCG8 gene that cause sitosterolemia result in a defective sterolin transporter and impair the elimination of plant sterols and, to a lesser degree, cholesterol from the body. These fatty substances build up in the arteries, skin, and other tissues, resulting in atherosclerosis, xanthomas, and the additional signs and symptoms of sitosterolemia. Excess plant sterols, such as sitosterol, in red blood cells likely make their cell membranes stiff and prone to rupture, leading to hemolytic anemia. Changes in the lipid composition of the membranes of red blood cells and platelets may account for the other blood abnormalities that sometimes occur in sitosterolemia. | sitosterolemia |
Is sitosterolemia 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. | sitosterolemia |
What are the treatments for sitosterolemia ? | These resources address the diagnosis or management of sitosterolemia: - Gene Review: Gene Review: Sitosterolemia - Genetic Testing Registry: Sitosterolemia - Massachusetts General Hospital: Lipid Metabolism 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 | sitosterolemia |
What is (are) Menkes syndrome ? | Menkes syndrome is a disorder that affects copper levels in the body. It is characterized by sparse, kinky hair; failure to gain weight and grow at the expected rate (failure to thrive); and deterioration of the nervous system. Additional signs and symptoms include weak muscle tone (hypotonia), sagging facial features, seizures, developmental delay, and intellectual disability. Children with Menkes syndrome typically begin to develop symptoms during infancy and often do not live past age 3. Early treatment with copper may improve the prognosis in some affected individuals. In rare cases, symptoms begin later in childhood. Occipital horn syndrome (sometimes called X-linked cutis laxa) is a less severe form of Menkes syndrome that begins in early to middle childhood. It is characterized by wedge-shaped calcium deposits in a bone at the base of the skull (the occipital bone), coarse hair, and loose skin and joints. | Menkes syndrome |
How many people are affected by Menkes syndrome ? | The incidence of Menkes syndrome and occipital horn syndrome is estimated to be 1 in 100,000 newborns. | Menkes syndrome |
What are the genetic changes related to Menkes syndrome ? | Mutations in the ATP7A gene cause Menkes syndrome. The ATP7A gene provides instructions for making a protein that is important for regulating copper levels in the body. Copper is necessary for many cellular functions, but it is toxic when present in excessive amounts. Mutations in the ATP7A gene result in poor distribution of copper to the body's cells. Copper accumulates in some tissues, such as the small intestine and kidneys, while the brain and other tissues have unusually low levels of copper. The decreased supply of copper can reduce the activity of numerous copper-containing enzymes that are necessary for the structure and function of bone, skin, hair, blood vessels, and the nervous system. The signs and symptoms of Menkes syndrome and occipital horn syndrome are caused by the reduced activity of these copper-containing enzymes. | Menkes syndrome |
Is Menkes syndrome inherited ? | Menkes syndrome is inherited in an X-linked recessive pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation 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. In about one-third of cases, Menkes syndrome is caused by new mutations in the ATP7A gene. People with a new mutation do not have a history of the disorder in their family. | Menkes syndrome |
What are the treatments for Menkes syndrome ? | These resources address the diagnosis or management of Menkes syndrome: - Gene Review: Gene Review: ATP7A-Related Copper Transport Disorders - Genetic Testing Registry: Menkes kinky-hair syndrome - MedlinePlus Encyclopedia: Copper in diet - MedlinePlus Encyclopedia: Menkes 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 | Menkes syndrome |
What is (are) progressive osseous heteroplasia ? | Progressive osseous heteroplasia is a disorder in which bone forms within skin and muscle tissue. Bone that forms outside the skeleton is called heterotopic or ectopic bone. In progressive osseous heteroplasia, ectopic bone formation begins in the deep layers of the skin (dermis and subcutaneous fat) and gradually moves into other tissues such as skeletal muscle and tendons. The bony lesions within the skin may be painful and may develop into open sores (ulcers). Over time, joints can become involved, resulting in impaired mobility. Signs and symptoms of progressive osseous heteroplasia usually become noticeable during infancy. In some affected individuals, however, this may not occur until later in childhood or in early adulthood. | progressive osseous heteroplasia |
How many people are affected by progressive osseous heteroplasia ? | Progressive osseous heteroplasia is a rare condition. Its exact incidence is unknown. | progressive osseous heteroplasia |
What are the genetic changes related to progressive osseous heteroplasia ? | Progressive osseous heteroplasia is caused by a mutation in the GNAS gene. The GNAS gene provides instructions for making one part of a protein complex called a guanine nucleotide-binding protein, or a G protein. In a process called signal transduction, G proteins trigger a complex network of signaling pathways that ultimately influence many cell functions. The protein produced from the GNAS gene is believed to play a key role in signaling pathways that help regulate the development of bone (osteogenesis), preventing bony tissue from being produced outside the skeleton. The GNAS gene mutations that cause progressive osseous heteroplasia disrupt the function of the G protein and impair its ability to regulate osteogenesis. As a result, bony tissue grows outside the skeleton and causes the complications associated with this disorder. | progressive osseous heteroplasia |
Is progressive osseous heteroplasia 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. People normally inherit one copy of each gene from their mother and one copy from their father. For most genes, both copies are active, or "turned on," in all cells. For a small subset of genes, however, only one of the two copies is active. For some of these genes, only the copy inherited from a person's father (the paternal copy) is active, while for other genes, only the copy inherited from a person's mother (the maternal copy) is active. These differences in gene activation based on the gene's parent of origin are caused by a phenomenon called genomic imprinting. The GNAS gene has a complex genomic imprinting pattern. In some cells of the body the maternal copy of the gene is active, while in others the paternal copy is active. Progressive osseous heteroplasia occurs when mutations affect the paternal copy of the gene. | progressive osseous heteroplasia |
What are the treatments for progressive osseous heteroplasia ? | These resources address the diagnosis or management of progressive osseous heteroplasia: - Genetic Testing Registry: Progressive osseous heteroplasia 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 | progressive osseous heteroplasia |
What is (are) task-specific focal dystonia ? | Task-specific focal dystonia is a movement disorder that interferes with the performance of particular tasks, such as writing, playing a musical instrument, or participating in a sport. Dystonias are a group of movement problems characterized by involuntary, sustained muscle contractions, tremors, and other uncontrolled movements. The term "focal" refers to a type of dystonia that affects a single part of the body, such as the hand or jaw. Researchers have described several forms of task-specific focal dystonia. The most common is writer's cramp, in which muscle cramps or spasms in the hand, wrist, or forearm interfere with holding a pen or pencil. Writer's cramp begins in the hand used for writing (the dominant hand) and is usually limited to that task, but with time it can spread to the other hand and affect other fine-motor activities such as shaving or typing. Musician's dystonia is a form of task-specific focal dystonia characterized by muscle cramps and spasms that occur while playing a musical instrument. This condition can affect amateur or professional musicians, and the location of the dystonia depends on the instrument. Some musicians (such as piano, guitar, and violin players) develop focal hand dystonia, which causes loss of fine-motor control in the hand and wrist muscles. This condition reduces finger coordination, speed, and endurance while playing. Musicians who play woodwind or brass instruments can develop what is known as embouchure dystonia. This condition causes muscle cramps or spasms involving the lips, tongue, or jaw, which prevents normal positioning of the mouth around the instrument's mouthpiece. Musician's dystonia often occurs only when playing a particular instrument. However, over time focal hand dystonia may impair other activities, and embouchure dystonia can worsen to affect eating and speech. Task-specific focal dystonia can affect people who play sports and engage in other occupations involving repetitive, highly practiced movements. For example, some golfers experience involuntary jerking of the wrists during putting, a condition known informally as "the yips." Cramps and spasms of the hand and arm muscles can also affect tennis players, billiards players, dart throwers, and other athletes. Additionally, task-specific dystonia has been reported in tailors, shoemakers, hair stylists, and people who frequently type or use a computer mouse. The abnormal movements associated with task-specific focal dystonia are usually painless, although they can cause anxiety when they interfere with musical performance and other activities. Severe cases can cause professional disability. | task-specific focal dystonia |
How many people are affected by task-specific focal dystonia ? | Task-specific focal dystonia affects an estimated 7 to 69 per million people in the general population. Musician's dystonia that is severe enough to impact performance occurs in about 1 percent of musicians. | task-specific focal dystonia |
What are the genetic changes related to task-specific focal dystonia ? | The causes of task-specific focal dystonia are unknown, although the disorder likely results from a combination of genetic and environmental factors. Certain genetic changes probably increase the likelihood of developing this condition, and environmental factors may trigger the onset of symptoms in people who are at risk. It is possible that the different forms of task-specific focal dystonia have different underlying causes. Having a family history of dystonia, particularly focal dystonia, is one of the only established risk factors for task-specific focal dystonia. Studies suggest that previous injury, changes in practice routine, and exposure to anti-psychotic drugs (which can cause other types of dystonia) are not major risk factors. Nor does the condition appear to be a form of performance anxiety. Task-specific focal dystonia may be associated with dysfunction in areas of the brain that regulate movement. In particular, researchers have found that at least some cases of the condition are related to malfunction of the basal ganglia, which are structures deep within the brain that help start and control movement. Although genetic factors are almost certainly involved in task-specific focal dystonia, no genes have been clearly associated with the condition. Researchers have looked for mutations in several genes known to be involved in other forms of dystonia, but these genetic changes do not appear to be a major cause of task-specific focal dystonia. Researchers are working to determine which genetic factors are related to this disorder. | task-specific focal dystonia |
Is task-specific focal dystonia inherited ? | Most cases of task-specific focal dystonia are sporadic, which means they occur in people with no history of the condition in their family. However, at least 10 percent of affected individuals have a family history of focal dystonia. (For example, writer's cramp and musician's dystonia have been reported to occur in the same family.) The dystonia often appears to have an autosomal dominant pattern of inheritance, based on the observation that some affected people have a parent with the condition. | task-specific focal dystonia |
What are the treatments for task-specific focal dystonia ? | These resources address the diagnosis or management of task-specific focal dystonia: - Dystonia Medical Research Foundation: How Is Dystonia Diagnosed? - Dystonia Medical Research Foundation: Treatments - Gene Review: Gene Review: Dystonia Overview - Genetic Testing Registry: Focal dystonia - Merck Manual Home Health Handbook: Dystonias 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 | task-specific focal dystonia |
What is (are) spinocerebellar ataxia type 6 ? | Spinocerebellar ataxia type 6 (SCA6) is a condition characterized by progressive problems with movement. People with this condition initially experience problems with coordination and balance (ataxia). Other early signs and symptoms of SCA6 include speech difficulties, involuntary eye movements (nystagmus), and double vision. Over time, individuals with SCA6 may develop loss of coordination in their arms, tremors, and uncontrolled muscle tensing (dystonia). Signs and symptoms of SCA6 typically begin in a person's forties or fifties but can appear anytime from childhood to late adulthood. Most people with this disorder require wheelchair assistance by the time they are in their sixties. | spinocerebellar ataxia type 6 |
How many people are affected by spinocerebellar ataxia type 6 ? | The worldwide prevalence of SCA6 is estimated to be less than 1 in 100,000 individuals. | spinocerebellar ataxia type 6 |
What are the genetic changes related to spinocerebellar ataxia type 6 ? | Mutations in the CACNA1A gene cause SCA6. The CACNA1A gene provides instructions for making a protein that forms a part of some calcium channels. These channels transport positively charged calcium atoms (calcium ions) across cell membranes. The movement of these ions is critical for normal signaling between nerve cells (neurons) in the brain and other parts of the nervous system. The CACNA1A gene provides instructions for making one part (the alpha-1 subunit) of a calcium channel called CaV2.1. CaV2.1 channels play an essential role in communication between neurons in the brain. The CACNA1A gene mutations that cause SCA6 involve a DNA segment known as a CAG trinucleotide repeat. This segment is made up of a series of three DNA building blocks (cytosine, adenine, and guanine) that appear multiple times in a row. Normally, the CAG segment is repeated 4 to 18 times within the gene. In people with SCA6, the CAG segment is repeated 20 to 33 times. People with 20 repeats tend to experience signs and symptoms of SCA6 beginning in late adulthood, while people with a larger number of repeats usually have signs and symptoms from mid-adulthood. An increase in the length of the CAG segment leads to the production of an abnormally long version of the alpha-1 subunit. This version of the subunit alters the location and function of the CaV2.1 channels. Normally the alpha-1 subunit is located within the cell membrane; the abnormal subunit is found in the cell membrane as well as in the fluid inside cells (cytoplasm), where it clusters together and forms clumps (aggregates). The effect these aggregates have on cell functioning is unknown. The lack of normal calcium channels in the cell membrane impairs cell communication between neurons in the brain. Diminished cell communication leads to cell death. Cells within the cerebellum, which is the part of the brain that coordinates movement, are particularly sensitive to the accumulation of these aggregates. Over time, a loss of cells in the cerebellum causes the movement problems characteristic of SCA6. | spinocerebellar ataxia type 6 |
Is spinocerebellar ataxia type 6 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 has one parent with the condition. As the altered CACNA1A gene is passed down from one generation to the next, the length of the CAG trinucleotide repeat often slightly increases. A larger number of repeats is usually associated with an earlier onset of signs and symptoms. This phenomenon is called anticipation. | spinocerebellar ataxia type 6 |
What are the treatments for spinocerebellar ataxia type 6 ? | These resources address the diagnosis or management of SCA6: - Gene Review: Gene Review: Spinocerebellar Ataxia Type 6 - Genetic Testing Registry: Spinocerebellar ataxia 6 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | spinocerebellar ataxia type 6 |
What is (are) Cole disease ? | Cole disease is a disorder that affects the skin. People with this disorder have areas of unusually light-colored skin (hypopigmentation), typically on the arms and legs, and spots of thickened skin on the palms of the hands and the soles of the feet (punctate palmoplantar keratoderma). These skin features are present at birth or develop in the first year of life. In some cases, individuals with Cole disease develop abnormal accumulations of the mineral calcium (calcifications) in the tendons, which can cause pain during movement. Calcifications may also occur in the skin or breast tissue. | Cole disease |
How many people are affected by Cole disease ? | Cole disease is a rare disease; its prevalence is unknown. Only a few affected families have been described in the medical literature. | Cole disease |
What are the genetic changes related to Cole disease ? | Cole disease is caused by mutations in the ENPP1 gene. This gene provides instructions for making a protein that helps to prevent minerals, including calcium, from being deposited in body tissues where they do not belong. It also plays a role in controlling cell signaling in response to the hormone insulin, through interaction between a part of the ENPP1 protein called the SMB2 domain and the insulin receptor. The insulin receptor is a protein that attaches (binds) to insulin and initiates cell signaling. Insulin plays many roles in the body, including regulating blood sugar levels by controlling how much sugar (in the form of glucose) is passed from the bloodstream into cells to be used as energy. Cell signaling in response to insulin is also important for the maintenance of the outer layer of skin (the epidermis). It helps control the transport of the pigment melanin from the cells in which it is produced (melanocytes) to epidermal cells called keratinocytes, and it is also involved in the development of keratinocytes. The mutations that cause Cole disease change the structure of the SMB2 domain, which alters its interaction with the insulin receptor and affects cell signaling. The resulting impairment of ENPP1's role in melanin transport and keratinocyte development leads to the hypopigmentation and keratoderma that occurs in Cole disease. The mutations may also impair ENPP1's control of calcification, which likely accounts for the abnormal calcium deposits that occur in some people with this disorder. For reasons that are unclear, the changes in insulin signaling resulting from these ENPP1 gene mutations do not seem to affect blood sugar control. | Cole disease |
Is Cole disease 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 of this disorder, 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. | Cole disease |
What are the treatments for Cole disease ? | These resources address the diagnosis or management of Cole disease: - Genetic Testing Registry: Cole disease These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Cole disease |
What is (are) pulmonary arterial hypertension ? | Pulmonary arterial hypertension is a progressive disorder characterized by abnormally high blood pressure (hypertension) in the pulmonary artery, the blood vessel that carries blood from the heart to the lungs. Pulmonary arterial hypertension is one form of a broader condition known as pulmonary hypertension. Pulmonary hypertension occurs when most of the very small arteries throughout the lungs narrow in diameter, which increases the resistance to blood flow through the lungs. To overcome the increased resistance, blood pressure increases in the pulmonary artery and in the right ventricle of the heart, which is the chamber that pumps blood into the pulmonary artery. Ultimately, the increased blood pressure can damage the right ventricle of the heart. Signs and symptoms of pulmonary arterial hypertension occur when increased blood pressure cannot fully overcome the elevated resistance. As a result, the flow of oxygenated blood from the lungs to the rest of the body is insufficient. Shortness of breath (dyspnea) during exertion and fainting spells are the most common symptoms of pulmonary arterial hypertension. People with this disorder may experience additional symptoms, particularly as the condition worsens. Other symptoms include dizziness, swelling (edema) of the ankles or legs, chest pain, and a rapid heart rate. | pulmonary arterial hypertension |
How many people are affected by pulmonary arterial hypertension ? | In the United States, about 1,000 new cases of pulmonary arterial hypertension are diagnosed each year. This disorder is twice as common in females as in males. | pulmonary arterial hypertension |
What are the genetic changes related to pulmonary arterial hypertension ? | Mutations in the BMPR2 gene are the most common genetic cause of pulmonary arterial hypertension. This gene plays a role in regulating the number of cells in certain tissues. Researchers suggest that a mutation in this gene promotes cell division or prevents cell death, resulting in an overgrowth of cells in small arteries throughout the lungs. As a result, these arteries narrow in diameter, which increases the resistance to blood flow. Blood pressure in the pulmonary artery and the right ventricle of the heart increases to overcome the increased resistance to blood flow. Mutations in several additional genes have also been found to cause pulmonary arterial hypertension, but they are much less common causes of the disorder than are BMPR2 gene mutations. Variations in other genes may increase the risk of developing pulmonary arterial hypertension or modify the course of the disease (usually making it more severe). Changes in as-yet-unidentified genes may also be associated with this condition. Although pulmonary arterial hypertension often occurs on its own, it can also be part of syndromes that affect many parts of the body. For example, this condition is occasionally found in people with systemic scleroderma, systemic lupus erythematosus, critical congenital heart disease, or Down syndrome. Researchers have also identified nongenetic factors that increase the risk of developing pulmonary arterial hypertension. These include certain drugs used as appetite suppressants and several illegal drugs, such as cocaine and methamphetamine. Pulmonary arterial hypertension is also a rare complication of certain infectious diseases, including HIV and schistosomiasis. | pulmonary arterial hypertension |
Is pulmonary arterial hypertension inherited ? | Pulmonary arterial hypertension is usually sporadic, which means it occurs in individuals with no known family history of the disorder. These non-familial cases are described as idiopathic pulmonary arterial hypertension. About 20 percent of these cases are caused by mutations in one of the genes known to be associated with the disease, but most of the time a causative gene mutation has not been identified. Inherited cases of this disorder are known as familial pulmonary arterial hypertension. When the condition is inherited, it most often has an autosomal dominant pattern of inheritance, which means one copy of an altered gene in each cell is sufficient to cause the disorder. However, many people with an altered gene never develop pulmonary arterial hypertension; this phenomenon is called reduced penetrance. | pulmonary arterial hypertension |
What are the treatments for pulmonary arterial hypertension ? | These resources address the diagnosis or management of pulmonary arterial hypertension: - Gene Review: Gene Review: Heritable Pulmonary Arterial Hypertension - Genetic Testing Registry: Primary pulmonary hypertension - Genetic Testing Registry: Primary pulmonary hypertension 2 - Genetic Testing Registry: Primary pulmonary hypertension 3 - Genetic Testing Registry: Primary pulmonary hypertension 4 - MedlinePlus Encyclopedia: Pulmonary hypertension 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 | pulmonary arterial hypertension |
What is (are) platyspondylic lethal skeletal dysplasia, Torrance type ? | Platyspondylic lethal skeletal dysplasia, Torrance type is a severe disorder of bone growth. People with this condition have very short arms and legs, underdeveloped pelvic bones, and unusually short fingers and toes (brachydactyly). This disorder is also characterized by flattened spinal bones (platyspondyly) and an exaggerated curvature of the lower back (lordosis). Infants with this condition are born with a small chest with short ribs that can restrict the growth and expansion of the lungs. As a result of these serious health problems, some affected fetuses do not survive to term. Infants born with platyspondylic lethal skeletal dysplasia, Torrance type usually die at birth or shortly thereafter from respiratory failure. A few affected people with milder signs and symptoms have lived into adulthood. | platyspondylic lethal skeletal dysplasia, Torrance type |
How many people are affected by platyspondylic lethal skeletal dysplasia, Torrance type ? | This condition is very rare; only a few affected individuals have been reported worldwide. | platyspondylic lethal skeletal dysplasia, Torrance type |
What are the genetic changes related to platyspondylic lethal skeletal dysplasia, Torrance type ? | Platyspondylic lethal skeletal dysplasia, Torrance type is one of a spectrum of skeletal disorders caused by mutations in the COL2A1 gene. This gene provides instructions for making a protein that forms type II collagen. This type of collagen is found mostly in the clear gel that fills the eyeball (the vitreous) and in cartilage. Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone, except for the cartilage that continues to cover and protect the ends of bones and is present in the nose and external ears. Type II collagen is essential for the normal development of bones and other connective tissues that form the body's supportive framework. All of the COL2A1 mutations that have been found to cause platyspondylic lethal skeletal dysplasia, Torrance type occur in a region of the protein called the C-propeptide domain. These mutations interfere with the assembly of type II collagen molecules, reducing the amount of this type of collagen in the body. Instead of forming collagen molecules, the abnormal COL2A1 protein builds up in cartilage cells (chondrocytes). These changes disrupt the normal development of bones and other connective tissues, leading to the skeletal abnormalities characteristic of platyspondylic lethal skeletal dysplasia, Torrance type. | platyspondylic lethal skeletal dysplasia, Torrance type |
Is platyspondylic lethal skeletal dysplasia, Torrance type 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. | platyspondylic lethal skeletal dysplasia, Torrance type |
What are the treatments for platyspondylic lethal skeletal dysplasia, Torrance type ? | These resources address the diagnosis or management of platyspondylic lethal skeletal dysplasia, Torrance type: - Genetic Testing Registry: Platyspondylic lethal skeletal dysplasia Torrance type - MedlinePlus Encyclopedia: Lordosis 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 | platyspondylic lethal skeletal dysplasia, Torrance type |
What is (are) PDGFRB-associated chronic eosinophilic leukemia ? | PDGFRB-associated chronic eosinophilic leukemia is a type of cancer of blood-forming cells. It is characterized by an elevated number of white blood cells called eosinophils in the blood. These cells help fight infections by certain parasites and are involved in the inflammation associated with allergic reactions. However, these circumstances do not account for the increased number of eosinophils in PDGFRB-associated chronic eosinophilic leukemia. Some people with this condition have an increased number of other types of white blood cells, such as neutrophils or mast cells, in addition to eosinophils. People with this condition can have an enlarged spleen (splenomegaly) or enlarged liver (hepatomegaly). Some affected individuals develop skin rashes, likely as a result of an abnormal immune response due to the increased number of eosinophils. | PDGFRB-associated chronic eosinophilic leukemia |
How many people are affected by PDGFRB-associated chronic eosinophilic leukemia ? | The exact prevalence of PDGFRB-associated chronic eosinophilic leukemia is unknown. For unknown reasons, males are up to nine times more likely than females to develop PDGFRB-associated chronic eosinophilic leukemia. | PDGFRB-associated chronic eosinophilic leukemia |
What are the genetic changes related to PDGFRB-associated chronic eosinophilic leukemia ? | PDGFRB-associated chronic eosinophilic leukemia is caused by genetic rearrangements that join part of the PDGFRB gene with part of another gene. At least 20 genes have been found that fuse with the PDGFRB gene to cause PDGFRB-associated chronic eosinophilic leukemia. The most common genetic abnormality in this condition results from a rearrangement (translocation) of genetic material that brings part of the PDGFRB gene on chromosome 5 together with part of the ETV6 gene on chromosome 12, creating the ETV6-PDGFRB fusion gene. The PDGFRB gene provides instructions for making a protein that plays a role in turning on (activating) signaling pathways that control many cell processes, including cell growth and division (proliferation). The ETV6 gene provides instructions for making a protein that turns off (represses) gene activity. This protein is important in development before birth and in regulating blood cell formation. The protein produced from the ETV6-PDGFRB fusion gene, called ETV6/PDGFR, functions differently than the proteins normally produced from the individual genes. Like the normal PDGFR protein, the ETV6/PDGFR fusion protein turns on signaling pathways. However, the fusion protein does not need to be turned on to be active, so the signaling pathways are constantly turned on (constitutively activated). The fusion protein is unable to repress gene activity regulated by the normal ETV6 protein, so gene activity is increased. The constitutively active signaling pathways and abnormal gene activity increase the proliferation and survival of cells. When the ETV6-PDGFRB fusion gene mutation occurs in cells that develop into blood cells, the growth of eosinophils (and occasionally other blood cells, such as neutrophils and mast cells) is poorly controlled, leading to PDGFRB-associated chronic eosinophilic leukemia. It is unclear why eosinophils are preferentially affected by this genetic change. | PDGFRB-associated chronic eosinophilic leukemia |
Is PDGFRB-associated chronic eosinophilic leukemia inherited ? | PDGFRB-associated chronic eosinophilic leukemia is not inherited and occurs in people with no history of the condition in their families. Chromosomal rearrangements that lead to a PDGFRB fusion gene are somatic mutations, which are mutations acquired during a person's lifetime and present only in certain cells. The somatic mutation occurs initially in a single cell, which continues to grow and divide, producing a group of cells with the same mutation (a clonal population). | PDGFRB-associated chronic eosinophilic leukemia |
What are the treatments for PDGFRB-associated chronic eosinophilic leukemia ? | These resources address the diagnosis or management of PDGFRB-associated chronic eosinophilic leukemia: - Cancer.Net: Leukemia--Eosinophilic: Treatment - Genetic Testing Registry: Myeloproliferative disorder, chronic, with eosinophilia - MedlinePlus Encyclopedia: Eosinophil Count--Absolute - Seattle Cancer Care Alliance: Hypereosinophilia 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 | PDGFRB-associated chronic eosinophilic leukemia |
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