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What is (are) spinocerebellar ataxia type 36 ? | Spinocerebellar ataxia type 36 (SCA36) is a condition characterized by progressive problems with movement that typically begin in mid-adulthood. People with this condition initially experience problems with coordination and balance (ataxia). Affected individuals often have exaggerated reflexes (hyperreflexia) and problems with speech (dysarthria). They also usually develop muscle twitches (fasciculations) of the tongue and over time, the muscles in the tongue waste away (atrophy). These tongue problems can cause difficulties swallowing liquids. As the condition progresses, individuals with SCA36 develop muscle atrophy in the legs, forearms, and hands. Another common feature of SCA36 is the atrophy of specialized nerve cells that control muscle movement (motor neurons), which can contribute to the tongue and limb muscle atrophy in affected individuals. Some people with SCA36 have abnormalities of the eye muscles, which can lead to involuntary eye movements (nystagmus), rapid eye movements (saccades), trouble moving the eyes side-to-side (oculomotor apraxia), and droopy eyelids (ptosis). Sensorineural hearing loss, which is hearing loss caused by changes in the inner ear, may also occur in people with SCA36. Brain imaging of people with SCA36 shows progressive atrophy of various parts of the brain, particularly within the cerebellum, which is the area of the brain involved in coordinating movements. Over time, the loss of cells in the cerebellum causes the movement problems characteristic of SCA36. In older affected individuals, the frontal lobes of the brain may show atrophy resulting in loss of executive function, which is the ability to plan and implement actions and develop problem-solving strategies. Signs and symptoms of SCA36 typically begin in a person's forties or fifties but can appear anytime during adulthood. People with SCA36 have a normal lifespan and are usually mobile for 15 to 20 years after they are diagnosed. | spinocerebellar ataxia type 36 |
How many people are affected by spinocerebellar ataxia type 36 ? | Approximately 100 individuals with SCA36 have been reported in the scientific literature. Almost all of these individuals have been from two regions: western Japan and the Costa de Morte in Galicia, Spain. | spinocerebellar ataxia type 36 |
What are the genetic changes related to spinocerebellar ataxia type 36 ? | SCA36 is caused by mutations in the NOP56 gene. The NOP56 gene provides instructions for making a protein called nucleolar protein 56, which is primarily found in the nucleus of nerve cells (neurons), particularly those in the cerebellum. This protein is one part (subunit) of the ribonucleoprotein complex, which is composed of proteins and molecules of RNA, DNA's chemical cousin. The ribonucleoprotein complex is needed to make cellular structures called ribosomes, which process the cell's genetic instructions to create proteins. The NOP56 gene mutations that cause SCA36 involve a string of six DNA building blocks (nucleotides) located in an area of the gene known as intron 1. This string of six nucleotides (known as a hexanucleotide) is represented by the letters GGCCTG and normally appears multiple times in a row. In healthy individuals, GGCCTG is repeated 3 to 14 times within the gene. In people with SCA36, GGCCTG is repeated at least 650 times. It is unclear if 15 to 649 repeats of this hexanucleotide cause any signs or symptoms. To make proteins from the genetic instructions carried in genes, a molecule called messenger RNA (mRNA) is formed. This molecule acts as a genetic blueprint for protein production. However, a large increase in the number of GGCCTG repeats in the NOP56 gene disrupts the normal structure of NOP56 mRNA. Abnormal NOP56 mRNA molecules form clumps called RNA foci within the nucleus of neurons. Other proteins become trapped in the RNA foci, where they cannot function. These proteins may be important for controlling gene activity or protein production. Additionally, researchers believe that the large expansion of the hexanucleotide repeat in the NOP56 gene may reduce the activity of a nearby gene called MIR1292. The MIR1292 gene provides instructions for making a type of RNA that regulates the activity (expression) of genes that produce proteins called glutamate receptors. These proteins are found on the surface of neurons and allow these cells to communicate with one another. A decrease in the production of Mir1292 RNA can lead to an increase in the production of glutamate receptors. The increased receptor activity may overexcite neurons, which disrupts normal communication between cells and can contribute to ataxia. The combination of RNA foci and overly excited neurons likely leads to the death of these cells over time. Because the NOP56 gene is especially active in neurons in the cerebellum, these cells are particularly affected by expansion of the gene, leading to cerebellar atrophy. Deterioration in this part of the brain leads to ataxia and the other signs and symptoms of SCA36. | spinocerebellar ataxia type 36 |
Is spinocerebellar ataxia type 36 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. In conditions that are caused by repeated segments of DNA, the number of repeats often increases when the altered gene is passed down from one generation to the next. Additionally, a larger number of repeats is usually associated with an earlier onset of signs and symptoms. This phenomenon is called anticipation. Some families affected by SCA36 have demonstrated anticipation while others have not. When anticipation is observed in SCA36, the mutation is most often passed down from the affected father. | spinocerebellar ataxia type 36 |
What are the treatments for spinocerebellar ataxia type 36 ? | These resources address the diagnosis or management of spinocerebellar ataxia type 36: - Ataxia Center at the University of Minnesota: Dominant Spinocerebellar Ataxias - Baylor College of Medicine: Parkinson's Disease Center and Movement Disorders Clinic: Ataxia - Gene Review: Gene Review: Spinocerebellar Ataxia Type 36 - Genetic Testing Registry: Spinocerebellar ataxia 36 - Johns Hopkins Medicine: Ataxia - The Ataxia Center at the University of Chicago: Autosomal Dominant Spinocerebellar Ataxia 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 36 |
What is (are) Laing distal myopathy ? | Laing distal myopathy is a condition that affects skeletal muscles, which are muscles that the body uses for movement. This disorder causes progressive muscle weakness that appears in childhood. The first sign of Laing distal myopathy is usually weakness in certain muscles in the feet and ankles. This weakness leads to tightening of the Achilles tendon (the band that connects the heel of the foot to the calf muscles), an inability to lift the first (big) toe, and a high-stepping walk. Months to years later, muscle weakness develops in the hands and wrists. Weakness in these muscles makes it difficult to lift the fingers, particularly the third and fourth fingers. Many affected people also experience hand tremors. In addition to muscle weakness in the hands and feet, Laing distal myopathy causes weakness in several muscles of the neck and face. A decade or more after the onset of symptoms, mild weakness also spreads to muscles in the legs, hips, and shoulders. Laing distal myopathy progresses very gradually, and most affected people remain mobile throughout life. Life expectancy is normal in people with this condition. | Laing distal myopathy |
How many people are affected by Laing distal myopathy ? | Although Laing distal myopathy is thought to be rare, its prevalence is unknown. Several families with the condition have been identified worldwide. | Laing distal myopathy |
What are the genetic changes related to Laing distal myopathy ? | Mutations in the MYH7 gene cause Laing distal myopathy. The MYH7 gene provides instructions for making a protein that is found in heart (cardiac) muscle and in type I skeletal muscle fibers. Type I fibers, which are also known as slow-twitch fibers, are one of two types of fibers that make up skeletal muscles. Type I fibers are the primary component of skeletal muscles that are resistant to fatigue. For example, muscles involved in posture, such as the neck muscles that hold the head steady, are made predominantly of type I fibers. In cardiac and skeletal muscle cells, the protein produced from the MYH7 gene forms part of a larger protein called type II myosin. This type of myosin generates the mechanical force that is needed for muscles to contract. In the heart, regular contractions of cardiac muscle pump blood to the rest of the body. The coordinated contraction and relaxation of skeletal muscles allow the body to move. It is unknown how mutations in the MYH7 gene cause progressive muscle weakness in people with Laing distal myopathy. Researchers have proposed that these mutations alter the structure of myosin in skeletal muscles, which prevents it from interacting with other proteins. The abnormal myosin gradually impairs the function of type I skeletal muscle fibers. In most people with Laing distal myopathy, the signs and symptoms of the disorder are limited to weakness of skeletal muscles. Although myosin made with the MYH7 protein is also found in cardiac muscle, it is unclear why heart problems are not a typical feature of this condition. | Laing distal myopathy |
Is Laing distal myopathy 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. A small percentage of cases result from new mutations in the gene. These cases occur in people with no history of the disorder in their family. | Laing distal myopathy |
What are the treatments for Laing distal myopathy ? | These resources address the diagnosis or management of Laing distal myopathy: - Gene Review: Gene Review: Laing Distal Myopathy - Genetic Testing Registry: Myopathy, distal, 1 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Laing distal myopathy |
What is (are) Graves disease ? | Graves disease is a condition that affects the function of the thyroid, which is a butterfly-shaped gland in the lower neck. The thyroid makes hormones that help regulate a wide variety of critical body functions. For example, thyroid hormones influence growth and development, body temperature, heart rate, menstrual cycles, and weight. In people with Graves disease, the thyroid is overactive and makes more hormones than the body needs. The condition usually appears in mid-adulthood, although it may occur at any age. Excess thyroid hormones can cause a variety of signs and symptoms. These include nervousness or anxiety, extreme tiredness (fatigue), a rapid and irregular heartbeat, hand tremors, frequent bowel movements or diarrhea, increased sweating and difficulty tolerating hot conditions, trouble sleeping, and weight loss in spite of an increased appetite. Affected women may have menstrual irregularities, such as an unusually light menstrual flow and infrequent periods. Some people with Graves disease develop an enlargement of the thyroid called a goiter. Depending on its size, the enlarged thyroid can cause the neck to look swollen and may interfere with breathing and swallowing. Between 25 and 50 percent of people with Graves disease have eye abnormalities, which are known as Graves ophthalmopathy. These eye problems can include swelling and inflammation, redness, dryness, puffy eyelids, and a gritty sensation like having sand or dirt in the eyes. Some people develop bulging of the eyes caused by inflammation of tissues behind the eyeball and "pulling back" (retraction) of the eyelids. Rarely, affected individuals have more serious eye problems, such as pain, double vision, and pinching (compression) of the optic nerve connecting the eye and the brain, which can cause vision loss. A small percentage of people with Graves disease develop a skin abnormality called pretibial myxedema or Graves dermopathy. This abnormality causes the skin on the front of the lower legs and the tops of the feet to become thick, lumpy, and red. It is not usually painful. | Graves disease |
How many people are affected by Graves disease ? | Graves disease affects about 1 in 200 people. The disease occurs more often in women than in men, which may be related to hormonal factors. Graves disease is the most common cause of thyroid overactivity (hyperthyroidism) in the United States. | Graves disease |
What are the genetic changes related to Graves disease ? | Graves disease is thought to result from a combination of genetic and environmental factors. Some of these factors have been identified, but many remain unknown. Graves disease is classified as an autoimmune disorder, one of a large group of conditions that occur when the immune system attacks the body's own tissues and organs. In people with Graves disease, the immune system creates a protein (antibody) called thyroid-stimulating immunoglobulin (TSI). TSI signals the thyroid to increase its production of hormones abnormally. The resulting overactivity of the thyroid causes many of the signs and symptoms of Graves disease. Studies suggest that immune system abnormalities also underlie Graves ophthalmopathy and pretibial myxedema. People with Graves disease have an increased risk of developing other autoimmune disorders, including rheumatoid arthritis, pernicious anemia, systemic lupus erythematosus, Addison disease, celiac disease, type 1 diabetes, and vitiligo. Variations in many genes have been studied as possible risk factors for Graves disease. Some of these genes are part of a family called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders (such as viruses and bacteria). Other genes that have been associated with Graves disease help regulate the immune system or are involved in normal thyroid function. Most of the genetic variations that have been discovered are thought to have a small impact on a person's overall risk of developing this condition. Other, nongenetic factors are also believed to play a role in Graves disease. These factors may trigger the condition in people who are at risk, although the mechanism is unclear. Potential triggers include changes in sex hormones (particularly in women), viral or bacterial infections, certain medications, and having too much or too little iodine (a substance critical for thyroid hormone production). Smoking increases the risk of eye problems and is associated with more severe eye abnormalities in people with Graves disease. | Graves disease |
Is Graves disease inherited ? | The inheritance pattern of Graves disease is unclear because many genetic and environmental factors appear to be involved. However, the condition can cluster in families, and having a close relative with Graves disease or another autoimmune disorder likely increases a person's risk of developing the condition. | Graves disease |
What are the treatments for Graves disease ? | These resources address the diagnosis or management of Graves disease: - American Thyroid Association: Thyroid Function Tests - Genetic Testing Registry: Graves disease 2 - Genetic Testing Registry: Graves disease 3 - Genetic Testing Registry: Graves disease, susceptibility to, X-linked 1 - Genetic Testing Registry: Graves' disease - Graves' Disease & Thyroid Foundation: Treatment Options - MedlinePlus Encyclopedia: TSI - National Institute of Diabetes and Digestive and Kidney Diseases: Thyroid Function Tests - Thyroid Disease Manager: Diagnosis and Treatment of Graves 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 | Graves disease |
What is (are) acral peeling skin syndrome ? | Acral peeling skin syndrome is a skin disorder characterized by painless peeling of the top layer of skin. The term "acral" refers to the fact that the skin peeling in this condition is most apparent on the hands and feet. Occasionally, peeling also occurs on the arms and legs. The peeling is usually evident from birth, although the condition can also begin in childhood or later in life. Skin peeling is made worse by exposure to heat, humidity and other forms of moisture, and friction. The underlying skin may be temporarily red and itchy, but it typically heals without scarring. Acral peeling skin syndrome is not associated with any other health problems. | acral peeling skin syndrome |
How many people are affected by acral peeling skin syndrome ? | Acral peeling skin syndrome is a rare condition, with several dozen cases reported in the medical literature. However, because its signs and symptoms tend to be mild and similar to those of other skin disorders, the condition is likely underdiagnosed. | acral peeling skin syndrome |
What are the genetic changes related to acral peeling skin syndrome ? | Acral peeling skin syndrome is caused by mutations in the TGM5 gene. This gene provides instructions for making an enzyme called transglutaminase 5, which is a component of the outer layer of skin (the epidermis). Transglutaminase 5 plays a critical role in the formation of a structure called the cornified cell envelope, which surrounds epidermal cells and helps the skin form a protective barrier between the body and its environment. TGM5 gene mutations reduce the production of transglutaminase 5 or prevent cells from making any of this protein. A shortage of transglutaminase 5 weakens the cornified cell envelope, which allows the outermost cells of the epidermis to separate easily from the underlying skin and peel off. This peeling is most noticeable on the hands and feet probably because those areas tend to be heavily exposed to moisture and friction. | acral peeling skin syndrome |
Is acral peeling skin syndrome inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | acral peeling skin syndrome |
What are the treatments for acral peeling skin syndrome ? | These resources address the diagnosis or management of acral peeling skin syndrome: - Birmingham Children's Hospital, National Health Service (UK) - Genetic Testing Registry: Peeling skin syndrome, acral 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 | acral peeling skin syndrome |
What is (are) Marfan syndrome ? | Marfan syndrome is a disorder that affects the connective tissue in many parts of the body. Connective tissue provides strength and flexibility to structures such as bones, ligaments, muscles, blood vessels, and heart valves. The signs and symptoms of Marfan syndrome vary widely in severity, timing of onset, and rate of progression. The two primary features of Marfan syndrome are vision problems caused by a dislocated lens (ectopia lentis) in one or both eyes and defects in the large blood vessel that distributes blood from the heart to the rest of the body (the aorta). The aorta can weaken and stretch, which may lead to a bulge in the blood vessel wall (an aneurysm). Stretching of the aorta may cause the aortic valve to leak, which can lead to a sudden tearing of the layers in the aorta wall (aortic dissection). Aortic aneurysm and dissection can be life threatening. Many people with Marfan syndrome have additional heart problems including a leak in the valve that connects two of the four chambers of the heart (mitral valve prolapse) or the valve that regulates blood flow from the heart into the aorta (aortic valve regurgitation). Leaks in these valves can cause shortness of breath, fatigue, and an irregular heartbeat felt as skipped or extra beats (palpitations). Individuals with Marfan syndrome are usually tall and slender, have elongated fingers and toes (arachnodactyly), and have an arm span that exceeds their body height. Other common features include a long and narrow face, crowded teeth, an abnormal curvature of the spine (scoliosis or kyphosis), and either a sunken chest (pectus excavatum) or a protruding chest (pectus carinatum). Some individuals develop an abnormal accumulation of air in the chest cavity that can result in the collapse of a lung (spontaneous pneumothorax). A membrane called the dura, which surrounds the brain and spinal cord, can be abnormally enlarged (dural ectasia) in people with Marfan syndrome. Dural ectasia can cause pain in the back, abdomen, legs, or head. Most individuals with Marfan syndrome have some degree of nearsightedness (myopia). Clouding of the lens (cataract) may occur in mid-adulthood, and increased pressure within the eye (glaucoma) occurs more frequently in people with Marfan syndrome than in those without the condition. The features of Marfan syndrome can become apparent anytime between infancy and adulthood. Depending on the onset and severity of signs and symptoms, Marfan can be fatal early in life; however, the majority of affected individuals survive into mid- to late adulthood. | Marfan syndrome |
How many people are affected by Marfan syndrome ? | The incidence of Marfan syndrome is approximately 1 in 5,000 worldwide. | Marfan syndrome |
What are the genetic changes related to Marfan syndrome ? | Mutations in the FBN1 gene cause Marfan syndrome. The FBN1 gene provides instructions for making a protein called fibrillin-1. Fibrillin-1 attaches (binds) to other fibrillin-1 proteins and other molecules to form threadlike filaments called microfibrils. Microfibrils become part of the fibers that provide strength and flexibility to connective tissue. Additionally, microfibrils store molecules called growth factors and release them at various times to control the growth and repair of tissues and organs throughout the body. A mutation in the FBN1 gene can reduce the amount of functional fibrillin-1 that is available to form microfibrils, which leads to decreased microfibril formation. As a result, excess growth factors are released and elasticity in many tissues is decreased, leading to overgrowth and instability of tissues. | Marfan syndrome |
Is Marfan 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. At least 25 percent of Marfan syndrome cases result from a new mutation in the FBN1 gene. These cases occur in people with no history of the disorder in their family. | Marfan syndrome |
What are the treatments for Marfan syndrome ? | These resources address the diagnosis or management of Marfan syndrome: - Gene Review: Gene Review: Marfan Syndrome - Genetic Testing Registry: Marfan syndrome - MarfanDX - MedlinePlus Encyclopedia: Aortic Dissection - MedlinePlus Encyclopedia: Marfan Syndrome - MedlinePlus Encyclopedia: Thoracic Aortic Aneurysm - National Marfan Foundation: 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 | Marfan syndrome |
What is (are) optic atrophy type 1 ? | Optic atrophy type 1 is a condition that affects vision. Individuals with this condition have progressive vision loss that typically begins within the first decade of life. The severity of the vision loss varies widely among affected people, even among members of the same family. People with this condition can range from having nearly normal vision to complete blindness. The vision loss usually progresses slowly. People with optic atrophy type 1 frequently have problems with color vision that make it difficult or impossible to distinguish between shades of blue and green. Other vision problems associated with this condition include a progressive narrowing of the field of vision (tunnel vision) and an abnormally pale appearance (pallor) of the nerve that relays visual information from the eye to the brain (optic nerve). Optic nerve pallor can be detected during an eye examination. | optic atrophy type 1 |
How many people are affected by optic atrophy type 1 ? | Optic atrophy type 1 is estimated to affect 1 in 50,000 people worldwide. This condition is more common in Denmark, where it affects approximately 1 in 10,000 people. | optic atrophy type 1 |
What are the genetic changes related to optic atrophy type 1 ? | Optic atrophy type 1 is caused by mutations in the OPA1 gene. The protein produced from this gene is made in many types of cells and tissues throughout the body. The OPA1 protein is found inside mitochondria, which are the energy-producing centers of cells. The OPA1 protein plays a key role in the organization of the shape and structure of the mitochondria and in the self-destruction of cells (apoptosis). The OPA1 protein is also involved in a process called oxidative phosphorylation, from which cells derive much of their energy. Additionally, the protein plays a role in the maintenance of the small amount of DNA within mitochondria, called mitochondrial DNA (mtDNA). Mutations in the OPA1 gene lead to overall dysfunction of mitochondria. The structure of the mitochondria become disorganized and cells are more susceptible to self-destruction. OPA1 gene mutations lead to mitochondria with reduced energy-producing capabilities. The maintenance of mtDNA is also sometimes impaired, resulting in mtDNA mutations. The vision problems experienced by people with optic atrophy type 1 are due to mitochondrial dysfunction, leading to the breakdown of structures that transmit visual information from the eyes to the brain. Affected individuals first experience a progressive loss of nerve cells within the retina, called retinal ganglion cells. The loss of these cells is followed by the degeneration (atrophy) of the optic nerve. The optic nerve is partly made up of specialized extensions of retinal ganglion cells called axons; when the retinal ganglion cells die, the optic nerve cannot transmit visual information to the brain normally. It is unclear why the OPA1 gene mutations that cause optic atrophy type 1 only affect the eyes. Retinal ganglion cells have many mitochondria and especially high energy requirements, which researchers believe may make them particularly vulnerable to mitochondrial dysfunction and decreases in energy production. Some individuals with optic atrophy type 1 do not have identified mutations in the OPA1 gene. In these cases, the cause of the condition is unknown. | optic atrophy type 1 |
Is optic atrophy type 1 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. | optic atrophy type 1 |
What are the treatments for optic atrophy type 1 ? | These resources address the diagnosis or management of optic atrophy type 1: - Gene Review: Gene Review: Optic Atrophy Type 1 - Genetic Testing Registry: Dominant hereditary optic atrophy - MedlinePlus Encyclopedia: Optic Nerve Atrophy - MedlinePlus Encyclopedia: Visual Acuity 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 | optic atrophy type 1 |
What is (are) intestinal pseudo-obstruction ? | Intestinal pseudo-obstruction is a condition characterized by impairment of the muscle contractions that move food through the digestive tract. The condition may arise from abnormalities of the gastrointestinal muscles themselves (myogenic) or from problems with the nerves that control the muscle contractions (neurogenic). When intestinal pseudo-obstruction occurs by itself, it is called primary or idiopathic intestinal pseudo-obstruction. The disorder can also develop as a complication of another medical condition; in these cases, it is called secondary intestinal pseudo-obstruction. Intestinal pseudo-obstruction leads to a buildup of partially digested food in the intestines. This buildup can cause abdominal swelling (distention) and pain, nausea, vomiting, and constipation or diarrhea. Affected individuals experience loss of appetite and impaired ability to absorb nutrients, which may lead to malnutrition. These symptoms resemble those of an intestinal blockage (obstruction), but in intestinal pseudo-obstruction no blockage is found. Some people with intestinal pseudo-obstruction have bladder dysfunction such as an inability to pass urine. Other features of this condition may include decreased muscle tone (hypotonia) or stiffness (spasticity), weakness in the muscles that control eye movement (ophthalmoplegia), intellectual disability, seizures, unusual facial features, or recurrent infections. Intestinal pseudo-obstruction can occur at any time of life. Its symptoms may range from mild to severe. Some affected individuals may require nutritional support. Depending on the severity of the condition, such support may include nutritional supplements, a feeding tube, or intravenous feedings (parenteral nutrition). | intestinal pseudo-obstruction |
How many people are affected by intestinal pseudo-obstruction ? | Primary intestinal pseudo-obstruction is a rare disorder. Its prevalence is unknown. The prevalence of secondary intestinal pseudo-obstruction is also unknown, but it is believed to be more common than the primary form. | intestinal pseudo-obstruction |
What are the genetic changes related to intestinal pseudo-obstruction ? | In some individuals with primary intestinal pseudo-obstruction, the condition is caused by mutations in the FLNA gene. This gene provides instructions for producing the protein filamin A, which helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Filamin A attaches (binds) to another protein called actin and helps it form the branching network of filaments that make up the cytoskeleton. Some individuals with primary intestinal pseudo-obstruction have FLNA gene mutations that result in an abnormally short filamin A protein. Others have duplications or deletions of genetic material in the FLNA gene. Researchers believe that these genetic changes may impair the function of the filamin A protein, causing abnormalities in the cytoskeleton of nerve cells (neurons) in the gastrointestinal tract. These abnormalities interfere with the nerves' ability to produce the coordinated waves of muscle contractions (peristalsis) that move food through the digestive tract. Deletions or duplications of genetic material that affect the FLNA gene can also include adjacent genes on the X chromosome. Changes in adjacent genes may account for some of the other signs and symptoms that can occur with intestinal pseudo-obstruction. Secondary intestinal pseudo-obstruction may result from other disorders that damage muscles or nerves, such as Parkinson disease, diabetes, or muscular dystrophy. Additionally, the condition is a feature of an inherited disease called mitochondrial neurogastrointestinal encephalopathy disease (MNGIE disease) that affects the energy-producing centers of cells (mitochondria). Infections, surgery, or certain drugs can also cause secondary intestinal pseudo-obstruction. In some affected individuals, the cause of intestinal pseudo-obstruction is unknown. Studies suggest that in some cases the condition may result from mutations in other genes that have not been identified. | intestinal pseudo-obstruction |
Is intestinal pseudo-obstruction inherited ? | Intestinal pseudo-obstruction is often not inherited. When it does run in families, it can have different inheritance patterns. Intestinal pseudo-obstruction caused by FLNA gene mutations is inherited in an X-linked recessive pattern. The FLNA gene is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. Intestinal pseudo-obstruction can also be inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In other families it is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. When intestinal pseudo-obstruction is inherited in an autosomal dominant or autosomal recessive pattern, the genetic cause of the disorder is unknown. When intestinal pseudo-obstruction is a feature of MNGIE disease, it is inherited in a mitochondrial pattern, which is also known as maternal inheritance. This pattern of inheritance applies to genes contained in mitochondrial DNA (mtDNA). Because egg cells, but not sperm cells, contribute mitochondria to the developing embryo, children can only inherit disorders resulting from mtDNA mutations from their mother. These disorders can appear in every generation of a family and can affect both males and females, but fathers do not pass traits associated with changes in mtDNA to their children. In some cases, the inheritance pattern is unknown. | intestinal pseudo-obstruction |
What are the treatments for intestinal pseudo-obstruction ? | These resources address the diagnosis or management of intestinal pseudo-obstruction: - Children's Hospital of Pittsburgh - Genetic Testing Registry: Intestinal pseudoobstruction neuronal chronic idiopathic X-linked - Genetic Testing Registry: Natal teeth, intestinal pseudoobstruction and patent ductus - Genetic Testing Registry: Visceral myopathy familial with external ophthalmoplegia - Genetic Testing Registry: Visceral neuropathy familial - Genetic Testing Registry: Visceral neuropathy, familial, autosomal dominant These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | intestinal pseudo-obstruction |
What is (are) CATSPER1-related nonsyndromic male infertility ? | CATSPER1-related nonsyndromic male infertility is a condition that affects the function of sperm, leading to an inability to father children. Males with this condition produce sperm that have decreased movement (motility). Affected men may also produce a smaller than usual number of sperm cells or sperm cells that are abnormally shaped. Men with CATSPER1-related nonsyndromic male infertility do not have any other symptoms related to this condition. | CATSPER1-related nonsyndromic male infertility |
How many people are affected by CATSPER1-related nonsyndromic male infertility ? | The prevalence of CATSPER1-related nonsyndromic male infertility is unknown. | CATSPER1-related nonsyndromic male infertility |
What are the genetic changes related to CATSPER1-related nonsyndromic male infertility ? | Mutations in the CATSPER1 gene cause CATSPER1-related nonsyndromic male infertility. The CATSPER1 gene provides instructions for producing a protein that is found in the tail of sperm cells. The CATSPER1 protein is involved in the movement of the sperm tail, which propels the sperm forward and is required for sperm cells to push through the outside membrane of the egg cell during fertilization. CATSPER1 gene mutations result in the production of a CATSPER1 protein that may be altered, nonfunctional, or quickly broken down (degraded) by the cell. Sperm cells missing a functional CATSPER1 protein have decreased motion in their tails and move more slowly than normal. Sperm cells lacking functional CATSPER1 protein cannot push through the outside membrane of the egg cell. As a result, sperm cells cannot reach the inside of the egg cell to achieve fertilization. | CATSPER1-related nonsyndromic male infertility |
Is CATSPER1-related nonsyndromic male infertility 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 symptoms of the condition. Males with two CATSPER1 gene mutations in each cell have CATSPER1-related nonsyndromic male infertility. Females with two CATSPER1 gene mutations in each cell have no symptoms because the mutations only affect sperm function, and women do not produce sperm. | CATSPER1-related nonsyndromic male infertility |
What are the treatments for CATSPER1-related nonsyndromic male infertility ? | These resources address the diagnosis or management of CATSPER1-related nonsyndromic male infertility: - Cleveland Clinic: Male Infertility - Gene Review: Gene Review: CATSPER-Related Male Infertility - Genetic Testing Registry: CATSPER-Related 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 | CATSPER1-related nonsyndromic male infertility |
What is (are) mucolipidosis III alpha/beta ? | Mucolipidosis III alpha/beta is a slowly progressive disorder that affects many parts of the body. Signs and symptoms of this condition typically appear around age 3. Individuals with mucolipidosis III alpha/beta grow slowly and have short stature. They also have stiff joints and dysostosis multiplex, which refers to multiple skeletal abnormalities seen on x-ray. Many affected individuals develop low bone mineral density (osteoporosis), which weakens the bones and makes them prone to fracture. Osteoporosis and progressive joint problems also cause bone pain that becomes more severe over time in people with mucolipidosis III alpha/beta. People with mucolipidosis III alpha/beta often have heart valve abnormalities and mild clouding of the clear covering of the eye (cornea). Their facial features become slightly thickened or "coarse" over time. Affected individuals may also develop frequent ear and respiratory infections. About half of people with this condition have mild intellectual disability or learning problems. Individuals with mucolipidosis III alpha/beta generally survive into adulthood, but they may have a shortened lifespan. | mucolipidosis III alpha/beta |
How many people are affected by mucolipidosis III alpha/beta ? | Mucolipidosis III alpha/beta is a rare disorder, although its exact prevalence is unknown. It is estimated to occur in about 1 in 100,000 to 400,000 individuals worldwide. | mucolipidosis III alpha/beta |
What are the genetic changes related to mucolipidosis III alpha/beta ? | Mutations in the GNPTAB gene cause mucolipidosis III alpha/beta. This gene provides instructions for making a part (subunit) of an enzyme called GlcNAc-1-phosphotransferase. This enzyme helps prepare certain newly made enzymes for transport to lysosomes. Lysosomes are compartments within the cell that use digestive enzymes to break down large molecules into smaller ones that can be reused by cells. GlcNAc-1-phosphotransferase is involved in the process of attaching a molecule called mannose-6-phosphate (M6P) to specific digestive enzymes. Just as luggage is tagged at the airport to direct it to the correct destination, enzymes are often "tagged" after they are made so they get to where they are needed in the cell. M6P acts as a tag that indicates a digestive enzyme should be transported to the lysosome. Mutations in the GNPTAB gene that cause mucolipidosis III alpha/beta result in reduced activity of GlcNAc-1-phosphotransferase. These mutations disrupt the tagging of digestive enzymes with M6P, which prevents many enzymes from reaching the lysosomes. Digestive enzymes that do not receive the M6P tag end up outside the cell, where they have increased activity. The shortage of digestive enzymes within lysosomes causes large molecules to accumulate there. Conditions that cause molecules to build up inside lysosomes, including mucolipidosis III alpha/beta, are called lysosomal storage disorders. The signs and symptoms of mucolipidosis III alpha/beta are most likely due to the shortage of digestive enzymes inside lysosomes and the effects these enzymes have outside the cell. Mutations in the GNPTAB gene can also cause a similar but more severe disorder called mucolipidosis II alpha/beta. These mutations completely eliminate the function of GlcNAc-1-phosphotransferase. Mucolipidosis III alpha/beta and mucolipidosis II alpha/beta represent two ends of a spectrum of disease severity. | mucolipidosis III alpha/beta |
Is mucolipidosis III alpha/beta 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. | mucolipidosis III alpha/beta |
What are the treatments for mucolipidosis III alpha/beta ? | These resources address the diagnosis or management of mucolipidosis III alpha/beta: - Gene Review: Gene Review: Mucolipidosis III Alpha/Beta - Genetic Testing Registry: Pseudo-Hurler polydystrophy - MedlinePlus Encyclopedia: Cloudy Cornea - MedlinePlus Encyclopedia: Heart Valves 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 | mucolipidosis III alpha/beta |
What is (are) catecholaminergic polymorphic ventricular tachycardia ? | Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a condition characterized by an abnormal heart rhythm (arrhythmia). As the heart rate increases in response to physical activity or emotional stress, it can trigger an abnormally fast and irregular heartbeat called ventricular tachycardia. Episodes of ventricular tachycardia can cause light-headedness, dizziness, and fainting (syncope). In people with CPVT, these episodes typically begin in childhood. If CPVT is not recognized and treated, an episode of ventricular tachycardia may cause the heart to stop beating (cardiac arrest), leading to sudden death. Researchers suspect that CPVT may be a significant cause of sudden death in children and young adults without recognized heart abnormalities. | catecholaminergic polymorphic ventricular tachycardia |
How many people are affected by catecholaminergic polymorphic ventricular tachycardia ? | The prevalence of CPVT is estimated to be about 1 in 10,000 people. However, the true prevalence of this condition is unknown. | catecholaminergic polymorphic ventricular tachycardia |
What are the genetic changes related to catecholaminergic polymorphic ventricular tachycardia ? | CPVT can result from mutations in two genes, RYR2 and CASQ2. RYR2 gene mutations cause about half of all cases, while mutations in the CASQ2 gene account for 1 percent to 2 percent of cases. In people without an identified mutation in one of these genes, the genetic cause of the disorder is unknown. The RYR2 and CASQ2 genes provide instructions for making proteins that help maintain a regular heartbeat. For the heart to beat normally, heart muscle cells called myocytes must tense (contract) and relax in a coordinated way. Both the RYR2 and CASQ2 proteins are involved in handling calcium within myocytes, which is critical for the regular contraction of these cells. Mutations in either the RYR2 or CASQ2 gene disrupt the handling of calcium within myocytes. During exercise or emotional stress, impaired calcium regulation in the heart can lead to ventricular tachycardia in people with CPVT. | catecholaminergic polymorphic ventricular tachycardia |
Is catecholaminergic polymorphic ventricular tachycardia inherited ? | When CPVT results from mutations in the RYR2 gene, it has an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means that one copy of the altered gene in each cell is sufficient to cause the disorder. In about half of cases, an affected person inherits an RYR2 gene mutation from one affected parent. The remaining cases result from new mutations in the RYR2 gene and occur in people with no history of the disorder in their family. When CPVT is caused by mutations in the CASQ2 gene, the condition has an autosomal recessive pattern of inheritance. Autosomal recessive inheritance means that 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. | catecholaminergic polymorphic ventricular tachycardia |
What are the treatments for catecholaminergic polymorphic ventricular tachycardia ? | These resources address the diagnosis or management of catecholaminergic polymorphic ventricular tachycardia: - Cleveland Clinic: Management of Arrhythmias - Gene Review: Gene Review: Catecholaminergic Polymorphic Ventricular Tachycardia - Genetic Testing Registry: Catecholaminergic polymorphic ventricular tachycardia - Genetic Testing Registry: Ventricular tachycardia, catecholaminergic polymorphic, 2 - MedlinePlus Encyclopedia: Fainting - MedlinePlus Encyclopedia: Ventricular Tachycardia 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 | catecholaminergic polymorphic ventricular tachycardia |
What is (are) nonsyndromic hearing loss ? | Nonsyndromic hearing loss is a partial or total loss of hearing that is not associated with other signs and symptoms. In contrast, syndromic hearing loss occurs with signs and symptoms affecting other parts of the body. Nonsyndromic hearing loss can be classified in several different ways. One common way is by the condition's pattern of inheritance: autosomal dominant (DFNA), autosomal recessive (DFNB), X-linked (DFNX), or mitochondrial (which does not have a special designation). Each of these types of hearing loss includes multiple subtypes. DFNA, DFNB, and DFNX subtypes are numbered in the order in which they were first described. For example, DFNA1 was the first type of autosomal dominant nonsyndromic hearing loss to be identified. The various inheritance patterns of nonsyndromic hearing loss are described in more detail below. The characteristics of nonsyndromic hearing loss vary among the different types. Hearing loss can affect one ear (unilateral) or both ears (bilateral). Degrees of hearing loss range from mild (difficulty understanding soft speech) to profound (inability to hear even very loud noises). The term "deafness" is often used to describe severe-to-profound hearing loss. Hearing loss can be stable, or it may be progressive, becoming more severe as a person gets older. Particular types of nonsyndromic hearing loss show distinctive patterns of hearing loss. For example, the loss may be more pronounced at high, middle, or low tones. Most forms of nonsyndromic hearing loss are described as sensorineural, which means they are associated with a permanent loss of hearing caused by damage to structures in the inner ear. The inner ear processes sound and sends the information to the brain in the form of electrical nerve impulses. Less commonly, nonsyndromic hearing loss is described as conductive, meaning it results from changes in the middle ear. The middle ear contains three tiny bones that help transfer sound from the eardrum to the inner ear. Some forms of nonsyndromic hearing loss, particularly a type called DFNX2, involve changes in both the inner ear and the middle ear. This combination is called mixed hearing loss. Depending on the type, nonsyndromic hearing loss can become apparent at any time from infancy to old age. Hearing loss that is present before a child learns to speak is classified as prelingual or congenital. Hearing loss that occurs after the development of speech is classified as postlingual. | nonsyndromic hearing loss |
How many people are affected by nonsyndromic hearing loss ? | Between 2 and 3 per 1,000 children in the United States are born with detectable hearing loss in one or both ears. The prevalence of hearing loss increases with age; the condition affects 1 in 8 people in the United States age 12 and older, or about 30 million people. By age 85, more than half of all people experience hearing loss. | nonsyndromic hearing loss |
What are the genetic changes related to nonsyndromic hearing loss ? | The causes of nonsyndromic hearing loss are complex. Researchers have identified more than 90 genes that, when altered, are associated with nonsyndromic hearing loss. Many of these genes are involved in the development and function of the inner ear. Mutations in these genes contribute to hearing loss by interfering with critical steps in processing sound. Different mutations in the same gene can be associated with different types of hearing loss, and some genes are associated with both syndromic and nonsyndromic forms. In many affected families, the factors contributing to hearing loss have not been identified. Most cases of nonsyndromic hearing loss are inherited in an autosomal recessive pattern. About half of all severe-to-profound autosomal recessive nonsyndromic hearing loss results from mutations in the GJB2 gene; these cases are designated DFNB1. The GJB2 gene provides instructions for making a protein called connexin 26, which is a member of the connexin protein family. Mutations in another connexin gene, GJB6, can also cause DFNB1. The GJB6 gene provides instructions for making a protein called connexin 30. Connexin proteins form channels called gap junctions, which allow communication between neighboring cells, including cells in the inner ear. Mutations in the GJB2 or GJB6 gene alter their respective connexin proteins, which changes the structure of gap junctions and may affect the function or survival of cells that are needed for hearing. The most common cause of moderate autosomal recessive nonsyndromic hearing loss is mutations in the STRC gene. These mutations cause a form of the condition known as DFNB16. Mutations in more than 60 other genes can also cause autosomal recessive nonsyndromic hearing loss. Many of these gene mutations have been found in one or a few families. Nonsyndromic hearing loss can also be inherited in an autosomal dominant pattern. Mutations in at least 30 genes have been identified in people with autosomal dominant nonsyndromic hearing loss; mutations in some of these genes (including GJB2 and GJB6) can also cause autosomal recessive forms of the condition. Although no single gene is associated with a majority of autosomal dominant nonsyndromic hearing loss cases, mutations in a few genes, such as KCNQ4 and TECTA, are relatively common. Mutations in many of the other genes associated with autosomal dominant nonsyndromic hearing loss have been found in only one or a few families. X-linked and mitochondrial forms of nonsyndromic hearing loss are rare. About half of all X-linked cases are caused by mutations in the POU3F4 gene. This form of the condition is designated DFNX2. Mutations in at least three other genes have also been identified in people with X-linked nonsyndromic hearing loss. Mitochondrial forms of hearing loss result from changes in mitochondrial DNA (mtDNA). Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA. Only a few mutations in mtDNA have been associated with hearing loss, and their role in the condition is still being studied. Mutations in some of the genes associated with nonsyndromic hearing loss can also cause syndromic forms of hearing loss, such as Usher syndrome (CDH23 and MYO7A, among others), Pendred syndrome (SLC26A4), Wolfram syndrome (WFS1), and Stickler syndrome (COL11A2). It is often unclear how mutations in the same gene can cause isolated hearing loss in some individuals and hearing loss with additional signs and symptoms in others. In addition to genetic changes, hearing loss can result from environmental factors or a combination of genetic risk and a person's environmental exposures. Environmental causes of hearing loss include certain medications, specific infections before or after birth, and exposure to loud noise over an extended period. Age is also a major risk factor for hearing loss. Age-related hearing loss (presbyacusis) is thought to have both genetic and environmental influences. | nonsyndromic hearing loss |
Is nonsyndromic hearing loss inherited ? | As discussed above, nonsyndromic hearing loss has different patterns of inheritance. Between 75 and 80 percent of cases are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Usually, each parent of an individual with autosomal recessive hearing loss carries one copy of the mutated gene but does not have hearing loss. Another 20 to 25 percent of nonsyndromic hearing loss has an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the condition. Most people with autosomal dominant hearing loss inherit an altered copy of the gene from a parent who also has hearing loss. Between 1 and 2 percent of cases have an X-linked pattern of inheritance. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. Males with X-linked nonsyndromic hearing loss tend to develop more severe hearing loss earlier in life than females who inherit a copy of the same gene mutation. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. Mitochondrial forms of the condition, which result from changes to mtDNA, account for less than 1 percent of all nonsyndromic hearing loss in the United States. These cases are inherited in a mitochondrial pattern, which is also known as maternal inheritance. This pattern of inheritance applies to genes contained in mtDNA. Because egg cells, but not sperm cells, contribute mitochondria to the developing embryo, children can only inherit disorders resulting from mtDNA mutations from their mother. These disorders can appear in every generation of a family and can affect both males and females, but fathers do not pass traits associated with changes in mtDNA to their children. In some cases, hearing loss occurs in people with no history of the condition in their family. These cases are described as sporadic, and the cause of the hearing loss is often unknown. When hearing loss results from environmental factors, it is not inherited. | nonsyndromic hearing loss |
What are the treatments for nonsyndromic hearing loss ? | These resources address the diagnosis or management of nonsyndromic hearing loss: - Baby's First Test: Hearing Loss - Gene Review: Gene Review: Deafness and Hereditary Hearing Loss Overview - Genetic Testing Registry: Deafness, X-linked - Genetic Testing Registry: Hereditary hearing loss and deafness - Genetic Testing Registry: Non-syndromic genetic deafness - MedlinePlus Encyclopedia: Age-related hearing loss - MedlinePlus Encyclopedia: Audiology - MedlinePlus Encyclopedia: Hearing loss - MedlinePlus Encyclopedia: Hearing or speech impairment - resources 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 | nonsyndromic hearing loss |
What is (are) congenital contractural arachnodactyly ? | Congenital contractural arachnodactyly is a disorder that affects many parts of the body. People with this condition typically are tall with long limbs (dolichostenomelia) and long, slender fingers and toes (arachnodactyly). They often have permanently bent joints (contractures) that can restrict movement in their hips, knees, ankles, or elbows. Additional features of congenital contractural arachnodactyly include underdeveloped muscles, a rounded upper back that also curves to the side (kyphoscoliosis), permanently bent fingers and toes (camptodactyly), ears that look "crumpled," and a protruding chest (pectus carinatum). Rarely, people with congenital contractural arachnodactyly have heart defects such as an enlargement of the blood vessel that distributes blood from the heart to the rest of the body (aortic root dilatation) or a leak in one of the valves that control blood flow through the heart (mitral valve prolapse). The life expectancy of individuals with congenital contractural arachnodactyly varies depending on the severity of symptoms but is typically not shortened. A rare, severe form of congenital contractural arachnodactyly involves both heart and digestive system abnormalities in addition to the skeletal features described above; individuals with this severe form of the condition usually do not live past infancy. | congenital contractural arachnodactyly |
How many people are affected by congenital contractural arachnodactyly ? | The prevalence of congenital contractural arachnodactyly is estimated to be less than 1 in 10,000 worldwide. | congenital contractural arachnodactyly |
What are the genetic changes related to congenital contractural arachnodactyly ? | Mutations in the FBN2 gene cause congenital contractural arachnodactyly. The FBN2 gene provides instructions for producing the fibrillin-2 protein. Fibrillin-2 binds to other proteins and molecules to form threadlike filaments called microfibrils. Microfibrils become part of the fibers that provide strength and flexibility to connective tissue that supports the body's joints and organs. Additionally, microfibrils regulate the activity of molecules called growth factors. Growth factors enable the growth and repair of tissues throughout the body. Mutations in the FBN2 gene can decrease fibrillin-2 production or result in the production of a protein with impaired function. As a result, microfibril formation is reduced, which probably weakens the structure of connective tissue and disrupts regulation of growth factor activity. The resulting abnormalities of connective tissue underlie the signs and symptoms of congenital contractural arachnodactyly. | congenital contractural arachnodactyly |
Is congenital contractural arachnodactyly 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 contractural arachnodactyly |
What are the treatments for congenital contractural arachnodactyly ? | These resources address the diagnosis or management of congenital contractural arachnodactyly: - Gene Review: Gene Review: Congenital Contractural Arachnodactyly - Genetic Testing Registry: Congenital contractural arachnodactyly - MedlinePlus Encyclopedia: Arachnodactyly - MedlinePlus Encyclopedia: Contracture Deformity - MedlinePlus Encyclopedia: Skeletal Limb Abnormalities 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 contractural arachnodactyly |
What is (are) Joubert syndrome ? | Joubert syndrome is a disorder that affects many parts of the body. The signs and symptoms of this condition vary among affected individuals, even among members of the same family. The hallmark feature of Joubert syndrome is a brain abnormality called the molar tooth sign, which can be seen on brain imaging studies such as magnetic resonance imaging (MRI). This sign results from the abnormal development of regions near the back of the brain called the cerebellar vermis and the brainstem. The molar tooth sign got its name because the characteristic brain abnormalities resemble the cross-section of a molar tooth when seen on an MRI. Most infants with Joubert syndrome have weak muscle tone (hypotonia) in infancy, which evolves into difficulty coordinating movements (ataxia) in early childhood. Other characteristic features of the condition include episodes of unusually fast or slow breathing in infancy and abnormal eye movements. Most affected individuals have delayed development and intellectual disability, which range from mild to severe. Distinctive facial features are also characteristic of Joubert syndrome; these include a broad forehead, arched eyebrows, droopy eyelids (ptosis), widely spaced eyes, low-set ears, and a triangle-shaped mouth. Joubert syndrome can include a broad range of additional signs and symptoms. The condition is sometimes associated with other eye abnormalities (such as retinal dystrophy, which can cause vision loss), kidney disease, liver disease, skeletal abnormalities (such as the presence of extra fingers and toes), and hormone (endocrine) problems. When the characteristic features of Joubert syndrome occur in combination with one or more of these additional signs and symptoms, researchers refer to the condition as "Joubert syndrome and related disorders (JSRD)." | Joubert syndrome |
How many people are affected by Joubert syndrome ? | Joubert syndrome is estimated to affect between 1 in 80,000 and 1 in 100,000 newborns. However, this estimate may be too low because Joubert syndrome has such a large range of possible features and is likely underdiagnosed. | Joubert syndrome |
What are the genetic changes related to Joubert syndrome ? | Joubert syndrome and related disorders can be caused by mutations in at least 10 genes. The proteins produced from these genes are known or suspected to play roles in cell structures called cilia. Cilia are microscopic, finger-like projections that stick out from the surface of cells and are involved in chemical signaling. Cilia are important for the structure and function of many types of cells, including brain cells (neurons) and certain cells in the kidneys and liver. Cilia are also necessary for the perception of sensory input (such as sight, hearing, and smell). Mutations in the genes associated with Joubert syndrome and related disorders lead to problems with the structure and function of cilia. Defects in these cell structures probably disrupt important chemical signaling pathways during development. Although researchers believe that defective cilia are responsible for most of the features of these disorders, it remains unclear how they lead to specific developmental abnormalities. Mutations in the 10 genes known to be associated with Joubert syndrome and related disorders only account for about half of all cases of these conditions. In the remaining cases, the genetic cause is unknown. | Joubert syndrome |
Is Joubert syndrome inherited ? | Joubert syndrome typically has an autosomal recessive pattern of inheritance, which means both copies of a gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they usually do not show signs and symptoms of the condition. Rare cases of Joubert syndrome are inherited in an X-linked recessive pattern. In these cases, the causative gene is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. | Joubert syndrome |
What are the treatments for Joubert syndrome ? | These resources address the diagnosis or management of Joubert syndrome: - Gene Review: Gene Review: Joubert Syndrome and Related Disorders - Genetic Testing Registry: Familial aplasia of the vermis - Genetic Testing Registry: Joubert syndrome 10 - Genetic Testing Registry: Joubert syndrome 2 - Genetic Testing Registry: Joubert syndrome 3 - Genetic Testing Registry: Joubert syndrome 4 - Genetic Testing Registry: Joubert syndrome 5 - Genetic Testing Registry: Joubert syndrome 6 - Genetic Testing Registry: Joubert syndrome 7 - Genetic Testing Registry: Joubert syndrome 8 - Genetic Testing Registry: Joubert syndrome 9 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Joubert syndrome |
What is (are) fibrodysplasia ossificans progressiva ? | Fibrodysplasia ossificans progressiva (FOP) is a disorder in which muscle tissue and connective tissue such as tendons and ligaments are gradually replaced by bone (ossified), forming bone outside the skeleton (extra-skeletal or heterotopic bone) that constrains movement. This process generally becomes noticeable in early childhood, starting with the neck and shoulders and proceeding down the body and into the limbs. Extra-skeletal bone formation causes progressive loss of mobility as the joints become affected. Inability to fully open the mouth may cause difficulty in speaking and eating. Over time, people with this disorder may experience malnutrition due to their eating problems. They may also have breathing difficulties as a result of extra bone formation around the rib cage that restricts expansion of the lungs. Any trauma to the muscles of an individual with fibrodysplasia ossificans progressiva, such as a fall or invasive medical procedures, may trigger episodes of muscle swelling and inflammation (myositis) followed by more rapid ossification in the injured area. Flare-ups may also be caused by viral illnesses such as influenza. People with fibrodysplasia ossificans progressiva are generally born with malformed big toes. This abnormality of the big toes is a characteristic feature that helps to distinguish this disorder from other bone and muscle problems. Affected individuals may also have short thumbs and other skeletal abnormalities. | fibrodysplasia ossificans progressiva |
How many people are affected by fibrodysplasia ossificans progressiva ? | Fibrodysplasia ossificans progressiva is a very rare disorder, believed to occur in approximately 1 in 2 million people worldwide. Several hundred cases have been reported. | fibrodysplasia ossificans progressiva |
What are the genetic changes related to fibrodysplasia ossificans progressiva ? | Mutations in the ACVR1 gene cause fibrodysplasia ossificans progressiva. The ACVR1 gene provides instructions for producing a member of a protein family called bone morphogenetic protein (BMP) type I receptors. The ACVR1 protein is found in many tissues of the body including skeletal muscle and cartilage. It helps to control the growth and development of the bones and muscles, including the gradual replacement of cartilage by bone (ossification) that occurs in normal skeletal maturation from birth to young adulthood. Researchers believe that a mutation in the ACVR1 gene may change the shape of the receptor under certain conditions and disrupt mechanisms that control the receptor's activity. As a result, the receptor may be constantly turned on (constitutive activation). Constitutive activation of the receptor causes overgrowth of bone and cartilage and fusion of joints, resulting in the signs and symptoms of fibrodysplasia ossificans progressiva. | fibrodysplasia ossificans progressiva |
Is fibrodysplasia ossificans progressiva 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 of fibrodysplasia ossificans progressiva result from new mutations in the gene. These cases occur in people with no history of the disorder in their family. In a small number of cases, an affected person has inherited the mutation from one affected parent. | fibrodysplasia ossificans progressiva |
What are the treatments for fibrodysplasia ossificans progressiva ? | These resources address the diagnosis or management of fibrodysplasia ossificans progressiva: - Genetic Testing Registry: Progressive myositis ossificans 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 | fibrodysplasia ossificans progressiva |
What is (are) ataxia with oculomotor apraxia ? | Ataxia with oculomotor apraxia is a condition characterized by progressive problems with movement. The hallmark of this condition is difficulty coordinating movements (ataxia), which is often the first symptom. Most affected people also have oculomotor apraxia, which makes it difficult to move their eyes side-to-side. People with oculomotor apraxia have to turn their head to see things in their side (peripheral) vision. There are multiple types of ataxia with oculomotor apraxia. The types are very similar but are caused by mutations in different genes. The two most common types (types 1 and 2) share features, in addition to ataxia and oculomotor apraxia, that include involuntary jerking movements (chorea), muscle twitches (myoclonus), and disturbances in nerve function (neuropathy). In type 1, ataxia beings around age 4; in type 2, ataxia begins around age 15. Chorea and myoclonus tend to disappear gradually in type 1; these movement problems persist throughout life in type 2. Individuals with type 1 often develop wasting (atrophy) in their hands and feet, which further impairs movement. Nearly all individuals with ataxia with oculomotor apraxia develop neuropathy, which leads to absent reflexes and weakness. Neuropathy causes many individuals with this condition to require wheelchair assistance, typically 10 to 15 years after the start of movement problems. Intelligence is usually not affected by this condition, but some people have intellectual disability. People with ataxia with oculomotor apraxia type 1 tend to have decreased amounts of a protein called albumin, which transports molecules in the blood. This decrease in albumin likely causes an increase in the amount of cholesterol circulating in the bloodstream. Increased cholesterol levels may raise a person's risk of developing heart disease. People with ataxia with oculomotor apraxia type 2 have increased blood cholesterol, but they have normal albumin levels. Individuals with type 2 tend to have high amounts of a protein called alpha-fetoprotein (AFP) in their blood. (An increase in the level of this protein is normally seen in the bloodstream of pregnant women.) Affected individuals may also have high amounts of a protein called creatine phosphokinase (CPK) in their blood. This protein is found mainly in muscle tissue. The effect of abnormally high levels of AFP or CPK in people with ataxia with oculomotor apraxia type 2 is unknown. | ataxia with oculomotor apraxia |
How many people are affected by ataxia with oculomotor apraxia ? | Ataxia with oculomotor apraxia is a rare condition. Type 1 is a common form of ataxia in Portugal and Japan. Type 2 is estimated to occur in 1 in 900,000 individuals worldwide. | ataxia with oculomotor apraxia |
What are the genetic changes related to ataxia with oculomotor apraxia ? | Mutations in the APTX and SETX genes cause ataxia with oculomotor apraxia types 1 and 2, respectively. These genes provide instructions for making proteins that are involved in DNA repair. Mutations in the APTX or SETX gene decrease the amount of functional protein that is available to repair damaged DNA, which leads to the accumulation of breaks in DNA. These breaks can be caused by natural and medical radiation or other environmental exposures, and also occur when chromosomes exchange genetic material in preparation for cell division. DNA damage that is not repaired causes the cell to be unstable and can lead to cell death. It is thought that nerve cells in the brain are particularly affected by cell death because these cells do not copy (replicate) themselves to replace cells that have been lost. The part of the brain involved in coordinating movements (the cerebellum) is especially affected. It is thought that the loss of brain cells in the cerebellum causes the movement problems characteristic of ataxia with oculomotor apraxia. Mutations in other genes are responsible for the rare types of ataxia with oculomotor apraxia. | ataxia with oculomotor apraxia |
Is ataxia with oculomotor apraxia 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. | ataxia with oculomotor apraxia |
What are the treatments for ataxia with oculomotor apraxia ? | These resources address the diagnosis or management of ataxia with oculomotor apraxia: - Gene Review: Gene Review: Ataxia with Oculomotor Apraxia Type 1 - Gene Review: Gene Review: Ataxia with Oculomotor Apraxia Type 2 - Genetic Testing Registry: Adult onset ataxia with oculomotor apraxia - Genetic Testing Registry: Ataxia-oculomotor apraxia 3 - Genetic Testing Registry: Ataxia-oculomotor apraxia 4 - Genetic Testing Registry: Spinocerebellar ataxia autosomal recessive 1 - MedlinePlus Encyclopedia: Apraxia 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 with oculomotor apraxia |
What is (are) SADDAN ? | SADDAN (severe achondroplasia with developmental delay and acanthosis nigricans) is a rare disorder of bone growth characterized by skeletal, brain, and skin abnormalities. All people with this condition have extremely short stature with particularly short arms and legs. Other features include unusual bowing of the leg bones; a small chest with short ribs and curved collar bones; short, broad fingers; and folds of extra skin on the arms and legs. Structural abnormalities of the brain cause seizures, profound developmental delay, and intellectual disability. Several affected individuals also have had episodes in which their breathing slows or stops for short periods (apnea). Acanthosis nigricans, a progressive skin disorder characterized by thick, dark, velvety skin, is another characteristic feature of SADDAN that develops in infancy or early childhood. | SADDAN |
How many people are affected by SADDAN ? | This disorder is very rare; it has been described in only a small number of individuals worldwide. | SADDAN |
What are the genetic changes related to SADDAN ? | Mutations in the FGFR3 gene cause SADDAN. The FGFR3 gene provides instructions for making a protein that is involved in the development and maintenance of bone and brain tissue. A mutation in this gene may cause the FGFR3 protein to be overly active, which leads to the disturbances in bone growth that are characteristic of this disorder. Researchers have not determined how the mutation disrupts brain development or causes acanthosis nigricans. | SADDAN |
Is SADDAN inherited ? | SADDAN is considered an autosomal dominant disorder because one mutated copy of the FGFR3 gene in each cell is sufficient to cause the condition. The few described cases of SADDAN have been caused by new mutations in the FGFR3 gene and occurred in people with no history of the disorder in their family. No individuals with this disorder are known to have had children; therefore, the disorder has not been passed to the next generation. | SADDAN |
What are the treatments for SADDAN ? | These resources address the diagnosis or management of SADDAN: - Gene Review: Gene Review: Achondroplasia - Genetic Testing Registry: Severe achondroplasia with developmental delay and acanthosis nigricans - MedlinePlus Encyclopedia: Acanthosis Nigricans These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | SADDAN |
What is (are) COL4A1-related brain small-vessel disease ? | COL4A1-related brain small-vessel disease is part of a group of conditions called the COL4A1-related disorders. The conditions in this group have a range of signs and symptoms that involve fragile blood vessels. COL4A1-related brain small-vessel disease is characterized by weakening of the blood vessels in the brain. Stroke is often the first symptom of this condition, typically occurring in mid-adulthood. In affected individuals, stroke is usually caused by bleeding in the brain (hemorrhagic stroke) rather than a lack of blood flow in the brain (ischemic stroke), although either type can occur. Individuals with this condition are at increased risk of having more than one stroke in their lifetime. People with COL4A1-related brain small vessel disease also have leukoencephalopathy, which is a change in a type of brain tissue called white matter that can be seen with magnetic resonance imaging (MRI). Affected individuals may also experience seizures and migraine headaches accompanied by visual sensations known as auras. Some people with COL4A1-related brain small-vessel disease have an eye abnormality called Axenfeld-Rieger anomaly. Axenfeld-Rieger anomaly involves underdevelopment and eventual tearing of the colored part of the eye (iris) and a pupil that is not in the center of the eye. Other eye problems experienced by people with COL4A1-related brain small-vessel disease include clouding of the lens of the eye (cataract) and the presence of arteries that twist and turn abnormally within the light-sensitive tissue at the back of the eye (arterial retinal tortuosity). Axenfeld-Rieger anomaly and cataract can cause impaired vision. Arterial retinal tortuosity can cause episodes of bleeding within the eye following any minor trauma to the eye, leading to temporary vision loss. The severity of the condition varies greatly among affected individuals. Some individuals with COL4A1-related brain small-vessel disease do not have any signs or symptoms of the condition. | COL4A1-related brain small-vessel disease |
How many people are affected by COL4A1-related brain small-vessel disease ? | COL4A1-related brain small-vessel disease is a rare condition, although the exact prevalence is unknown. At least 50 individuals with this condition have been described in the scientific literature. | COL4A1-related brain small-vessel disease |
What are the genetic changes related to COL4A1-related brain small-vessel disease ? | As the name suggests, mutations in the COL4A1 gene cause COL4A1-related brain small vessel disease. The COL4A1 gene provides instructions for making one component of a protein called type IV collagen. Type IV collagen molecules attach to each other to form complex protein networks. These protein networks are the main components of basement membranes, which are thin sheet-like structures that separate and support cells in many tissues. Type IV collagen networks play an important role in the basement membranes in virtually all tissues throughout the body, particularly the basement membranes surrounding the body's blood vessels (vasculature). The COL4A1 gene mutations that cause COL4A1-related brain small-vessel disease result in the production of a protein that disrupts the structure of type IV collagen. As a result, type IV collagen molecules cannot attach to each other to form the protein networks in basement membranes. Basement membranes without these networks are unstable, leading to weakening of the tissues that they surround. In people with COL4A1-related brain small-vessel disease, the vasculature in the brain weakens, which can lead to blood vessel breakage and stroke. Similar blood vessel weakness and breakage occurs in the eyes of some affected individuals. | COL4A1-related brain small-vessel disease |
Is COL4A1-related brain small-vessel 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, an affected person has one parent with the condition. Rarely, new mutations in the gene occur in people with no history of the disorder in their family. | COL4A1-related brain small-vessel disease |
What are the treatments for COL4A1-related brain small-vessel disease ? | These resources address the diagnosis or management of COL4A1-related brain small-vessel disease: - Gene Review: Gene Review: COL4A1-Related Disorders - Genetic Testing Registry: Brain small vessel disease with hemorrhage 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 | COL4A1-related brain small-vessel disease |
What is (are) Stargardt macular degeneration ? | Stargardt macular degeneration is a genetic eye disorder that causes progressive vision loss. This disorder affects the retina, the specialized light-sensitive tissue that lines the back of the eye. Specifically, Stargardt macular degeneration affects a small area near the center of the retina called the macula. The macula is responsible for sharp central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces. In most people with Stargardt macular degeneration, a fatty yellow pigment (lipofuscin) builds up in cells underlying the macula. Over time, the abnormal accumulation of this substance can damage cells that are critical for clear central vision. In addition to central vision loss, people with Stargardt macular degeneration have problems with night vision that can make it difficult to navigate in low light. Some affected individuals also have impaired color vision. The signs and symptoms of Stargardt macular degeneration typically appear in late childhood to early adulthood and worsen over time. | Stargardt macular degeneration |
How many people are affected by Stargardt macular degeneration ? | Stargardt macular degeneration is the most common form of juvenile macular degeneration, the signs and symptoms of which begin in childhood. The estimated prevalence of Stargardt macular degeneration is 1 in 8,000 to 10,000 individuals. | Stargardt macular degeneration |
What are the genetic changes related to Stargardt macular degeneration ? | In most cases, Stargardt macular degeneration is caused by mutations in the ABCA4 gene. Less often, mutations in the ELOVL4 gene cause this condition. The ABCA4 and ELOVL4 genes provide instructions for making proteins that are found in light-sensing (photoreceptor) cells in the retina. The ABCA4 protein transports potentially toxic substances out of photoreceptor cells. These substances form after phototransduction, the process by which light entering the eye is converted into electrical signals that are transmitted to the brain. Mutations in the ABCA4 gene prevent the ABCA4 protein from removing toxic byproducts from photoreceptor cells. These toxic substances build up and form lipofuscin in the photoreceptor cells and the surrounding cells of the retina, eventually causing cell death. Loss of cells in the retina causes the progressive vision loss characteristic of Stargardt macular degeneration. The ELOVL4 protein plays a role in making a group of fats called very long-chain fatty acids. The ELOVL4 protein is primarily active (expressed) in the retina, but is also expressed in the brain and skin. The function of very long-chain fatty acids within the retina is unknown. Mutations in the ELOVL4 gene lead to the formation of ELOVL4 protein clumps (aggregates) that build up and may interfere with retinal cell functions, ultimately leading to cell death. | Stargardt macular degeneration |
Is Stargardt macular degeneration inherited ? | Stargardt macular degeneration can have different inheritance patterns. When mutations in the ABCA4 gene cause this condition, it is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. When this condition is caused by mutations in the ELOVL4 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. | Stargardt macular degeneration |
What are the treatments for Stargardt macular degeneration ? | These resources address the diagnosis or management of Stargardt macular degeneration: - Genetic Testing Registry: Stargardt Disease 3 - Genetic Testing Registry: Stargardt disease 1 - Genetic Testing Registry: Stargardt disease 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 | Stargardt macular degeneration |
What is (are) 3-hydroxy-3-methylglutaryl-CoA lyase deficiency ? | 3-hydroxy-3-methylglutaryl-CoA lyase deficiency (also known as HMG-CoA lyase deficiency) is an uncommon inherited disorder in which the body cannot process a particular protein building block (amino acid) called leucine. Additionally, the disorder prevents the body from making ketones, which are used for energy during periods without food (fasting). The signs and symptoms of HMG-CoA lyase deficiency usually appear within the first year of life. The condition causes episodes of vomiting, diarrhea, dehydration, extreme tiredness (lethargy), and weak muscle tone (hypotonia). During an episode, blood sugar levels can become dangerously low (hypoglycemia), and a buildup of harmful compounds can cause the blood to become too acidic (metabolic acidosis). If untreated, the disorder can lead to breathing problems, convulsions, coma, and death. Episodes are often triggered by an infection, fasting, strenuous exercise, or other types of stress. HMG-CoA lyase deficiency is sometimes mistaken for Reye syndrome, a severe disorder that develops 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. | 3-hydroxy-3-methylglutaryl-CoA lyase deficiency |
How many people are affected by 3-hydroxy-3-methylglutaryl-CoA lyase deficiency ? | HMG-CoA lyase deficiency is a rare condition; it has been reported in fewer than 100 individuals worldwide. Most people diagnosed with this disorder have been from Saudi Arabia, Portugal, or Spain. | 3-hydroxy-3-methylglutaryl-CoA lyase deficiency |
What are the genetic changes related to 3-hydroxy-3-methylglutaryl-CoA lyase deficiency ? | Mutations in the HMGCL gene cause HMG-CoA lyase deficiency. The HMGCL gene provides instructions for making an enzyme known as 3-hydroxymethyl-3-methylglutaryl-coenzyme A lyase (HMG-CoA lyase). This enzyme plays a critical role in breaking down dietary proteins and fats for energy. Specifically, it is responsible for processing leucine, an amino acid that is part of many proteins. HMG-CoA lyase also produces ketones during the breakdown of fats. Ketones are compounds that certain organs and tissues, particularly the brain, use for energy when the simple sugar glucose is not available. For example, ketones are important sources of energy during periods of fasting. If a mutation in the HMGCL gene reduces or eliminates the activity of HMG-CoA lyase, the body is unable to process leucine or make ketones properly. When leucine is not processed normally, a buildup of chemical byproducts called organic acids can result in metabolic acidosis. A shortage of ketones often leads to hypoglycemia. Metabolic acidosis and hypoglycemia can damage cells, particularly in the brain, resulting in serious illness in children with HMG-CoA lyase deficiency. | 3-hydroxy-3-methylglutaryl-CoA lyase deficiency |
Is 3-hydroxy-3-methylglutaryl-CoA lyase deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | 3-hydroxy-3-methylglutaryl-CoA lyase deficiency |
What are the treatments for 3-hydroxy-3-methylglutaryl-CoA lyase deficiency ? | These resources address the diagnosis or management of HMG-CoA lyase deficiency: - Baby's First Test - Genetic Testing Registry: Deficiency of hydroxymethylglutaryl-CoA lyase 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 | 3-hydroxy-3-methylglutaryl-CoA lyase deficiency |
What is (are) Czech dysplasia ? | Czech dysplasia is an inherited condition that affects joint function and bone development. People with this condition have joint pain (osteoarthritis) that begins in adolescence or early adulthood. The joint pain mainly affects the hips, knees, shoulders, and spine and may impair mobility. People with Czech dysplasia often have shortened bones in their third and fourth toes, which make their first two toes appear unusually long. Affected individuals may have flattened bones of the spine (platyspondyly) or an abnormal spinal curvature, such as a rounded upper back that also curves to the side (kyphoscoliosis). Some people with Czech dysplasia have progressive hearing loss. | Czech dysplasia |
How many people are affected by Czech dysplasia ? | The prevalence of Czech dysplasia is unknown; at least 11 families have been affected. Most of these families reside in the Czech Republic. | Czech dysplasia |
What are the genetic changes related to Czech dysplasia ? | Czech dysplasia is caused by a particular mutation in the COL2A1 gene. The COL2A1 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. Mutations in the COL2A1 gene interfere with the assembly of type II collagen molecules, which prevents bones and other connective tissues from developing properly. | Czech dysplasia |
Is Czech dysplasia inherited ? | Czech dysplasia is inherited in an autosomal dominant pattern, which means one copy of the altered COL2A1 gene in each cell is sufficient to cause the disorder. All known individuals with Czech dysplasia inherited the mutation from a parent with the condition. | Czech dysplasia |
What are the treatments for Czech dysplasia ? | These resources address the diagnosis or management of Czech dysplasia: - Genetic Testing Registry: Czech dysplasia metatarsal 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 | Czech dysplasia |
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