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What is (are) Alpers-Huttenlocher syndrome ? | Alpers-Huttenlocher syndrome is one of the most severe of a group of conditions called the POLG-related disorders. The conditions in this group feature a range of similar signs and symptoms involving muscle-, nerve-, and brain-related functions. Alpers-Huttenlocher syndrome typically becomes apparent in children between ages 2 and 4. People with this condition usually have three characteristic features: recurrent seizures that do not improve with treatment (intractable epilepsy), loss of mental and movement abilities (psychomotor regression), and liver disease. People with Alpers-Huttenlocher syndrome usually have additional signs and symptoms. Most have problems with coordination and balance (ataxia) and disturbances in nerve function (neuropathy). Neuropathy can lead to abnormal or absent reflexes (areflexia). In addition, affected individuals may develop weak muscle tone (hypotonia) that worsens until they lose the ability to control their muscles and movement. Some people with Alpers-Huttenlocher syndrome lose the ability to walk, sit, or feed themselves. Other movement-related symptoms in affected individuals can include involuntary muscle twitches (myoclonus), uncontrollable movements of the limbs (choreoathetosis), or a pattern of movement abnormalities known as parkinsonism. Affected individuals may have other brain-related signs and symptoms. Migraine headaches, often with visual sensations or auras, are common. Additionally, people with this condition may have decreased brain function that is demonstrated as sleepiness, inability to concentrate, irritability, or loss of language skills or memory. Some people with the condition may lose their eyesight or hearing. People with Alpers-Huttenlocher syndrome can survive from a few months to more than 10 years after the condition first appears. | Alpers-Huttenlocher syndrome |
How many people are affected by Alpers-Huttenlocher syndrome ? | The prevalence of Alpers-Huttenlocher syndrome is approximately 1 in 100,000 individuals. | Alpers-Huttenlocher syndrome |
What are the genetic changes related to Alpers-Huttenlocher syndrome ? | Alpers-Huttenlocher syndrome is caused by mutations in the POLG gene. This gene provides instructions for making one part, the alpha subunit, of a protein called polymerase gamma (pol ). Pol functions in mitochondria, which are structures within cells that use oxygen to convert the energy from food into a form cells can use. Mitochondria each contain a small amount of DNA, known as mitochondrial DNA (mtDNA), which is essential for the normal function of these structures. Pol "reads" sequences of mtDNA and uses them as templates to produce new copies of mtDNA in a process called DNA replication. Most POLG gene mutations change single protein building blocks (amino acids) in the alpha subunit of pol . These changes result in a mutated pol that has a reduced ability to replicate DNA. Although the mechanism is unknown, mutations in the POLG gene often result in a reduced number of copies of mtDNA (mtDNA depletion), particularly in muscle, brain, and liver cells. MtDNA depletion causes a decrease in cellular energy, which could account for the signs and symptoms of Alpers-Huttenlocher syndrome. A mutation in the POLG gene has not been identified in approximately 13 percent of people diagnosed with Alpers-Huttenlocher syndrome. Researchers are working to identify other genes that may be responsible for the condition. | Alpers-Huttenlocher syndrome |
Is Alpers-Huttenlocher 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. | Alpers-Huttenlocher syndrome |
What are the treatments for Alpers-Huttenlocher syndrome ? | These resources address the diagnosis or management of Alpers-Huttenlocher syndrome: - Gene Review: Gene Review: POLG-Related Disorders - Genetic Testing Registry: Progressive sclerosing poliodystrophy - United Mitochondrial Disease Foundation: Diagnosis of Mitochondrial 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 | Alpers-Huttenlocher syndrome |
What is (are) juvenile Batten disease ? | Juvenile Batten disease is an inherited disorder that primarily affects the nervous system. After a few years of normal development, children with this condition develop progressive vision loss, intellectual and motor disability, speech difficulties, and seizures. Vision impairment is often the first noticeable sign of juvenile Batten disease, beginning between the ages of 4 and 8 years. Vision loss tends to progress rapidly, eventually resulting in blindness. After vision impairment has begun, children with juvenile Batten disease experience the loss of previously acquired skills (developmental regression), usually beginning with the ability to speak in complete sentences. Affected children also have difficulty learning new information. In addition to the intellectual decline, affected children lose motor skills such as the ability to walk or sit. They also develop movement abnormalities that include rigidity or stiffness, slow or diminished movements (hypokinesia), and stooped posture. Affected children may have recurrent seizures (epilepsy), heart problems, behavioral problems, difficulty sleeping, and problems with attention that begin in mid- to late childhood. Most people with juvenile Batten disease live into their twenties or thirties. Juvenile Batten disease is one of a group of disorders known as neuronal ceroid lipofuscinoses (NCLs). These disorders all affect the nervous system and typically cause progressive problems with vision, movement, and thinking ability. The different types of NCLs are distinguished by the age at which signs and symptoms first appear. Some people refer to the entire group of NCLs as Batten disease, while others limit that designation to the juvenile form of the disorder. | juvenile Batten disease |
How many people are affected by juvenile Batten disease ? | Juvenile Batten disease is the most common type of NCL, but its exact prevalence is unknown. Collectively, all forms of NCL affect an estimated 1 in 100,000 individuals worldwide. NCLs are more common in Finland, where approximately 1 in 12,500 individuals are affected. | juvenile Batten disease |
What are the genetic changes related to juvenile Batten disease ? | Most cases of juvenile Batten disease are caused by mutations in the CLN3 gene. This gene provides instructions for making a protein whose function is unknown. It is unclear how mutations in the CLN3 gene lead to the characteristic features of juvenile Batten disease. These mutations somehow disrupt the function of cellular structures called lysosomes. Lysosomes are compartments in the cell that normally digest and recycle different types of molecules. Lysosome malfunction leads to a buildup of fatty substances called lipopigments within these cell structures. These accumulations occur in cells throughout the body, but neurons in the brain seem to be particularly vulnerable to the damage caused by lipopigments. The progressive death of cells, especially in the brain, leads to vision loss, seizures, and intellectual decline in people with juvenile Batten disease. A small percentage of cases of juvenile Batten disease are caused by mutations in other genes. Many of these genes are involved in lysosomal function, and when mutated, can cause this or other forms of NCL. | juvenile Batten disease |
Is juvenile Batten disease 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. | juvenile Batten disease |
What are the treatments for juvenile Batten disease ? | These resources address the diagnosis or management of juvenile Batten disease: - Batten Disease Diagnostic and Clinical Research Center at the University of Rochester Medical Center - Batten Disease Support and Research Association: Centers of Excellence - Gene Review: Gene Review: Neuronal Ceroid-Lipofuscinoses - Genetic Testing Registry: Juvenile neuronal ceroid lipofuscinosis 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 | juvenile Batten disease |
What is (are) spinal muscular atrophy with progressive myoclonic epilepsy ? | Spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) is a neurological condition that causes muscle weakness and wasting (atrophy) and a combination of seizures and uncontrollable muscle jerks (myoclonic epilepsy). In individuals with SMA-PME, spinal muscular atrophy results from a loss of specialized nerve cells, called motor neurons, in the spinal cord and the part of the brain that is connected to the spinal cord (the brainstem). After a few years of normal development, affected children begin experiencing muscle weakness and atrophy in the lower limbs, causing difficulty walking and frequent falls. The muscles in the upper limbs are later affected, and soon the muscle weakness and atrophy spreads throughout the body. Once weakness reaches the muscles used for breathing and swallowing, it leads to life-threatening breathing problems and increased susceptibility to pneumonia. A few years after the muscle weakness begins, affected individuals start to experience recurrent seizures (epilepsy). Most people with SMA-PME have a variety of seizure types. In addition to myoclonic epilepsy, they may have generalized tonic-clonic seizures (also known as grand mal seizures), which cause muscle rigidity, convulsions, and loss of consciousness. Affected individuals can also have absence seizures, which cause loss of consciousness for a short period that may or may not be accompanied by muscle jerks. In SMA-PME, seizures often increase in frequency over time and are usually not well-controlled with medication. Individuals with SMA-PME may also have episodes of rhythmic shaking (tremors), usually in the hands; these tremors are not thought to be related to epilepsy. Some people with SMA-PME develop hearing loss caused by nerve damage in the inner ear (sensorineural hearing loss). Individuals with SMA-PME have a shortened lifespan; they generally live into late childhood or early adulthood. The cause of death is often respiratory failure or pneumonia. | spinal muscular atrophy with progressive myoclonic epilepsy |
How many people are affected by spinal muscular atrophy with progressive myoclonic epilepsy ? | SMA-PME is a rare disorder; approximately a dozen affected families have been described in the scientific literature. | spinal muscular atrophy with progressive myoclonic epilepsy |
What are the genetic changes related to spinal muscular atrophy with progressive myoclonic epilepsy ? | SMA-PME is caused by mutations in the ASAH1 gene. This gene provides instructions for making an enzyme called acid ceramidase. This enzyme is found in lysosomes, which are cell compartments that digest and recycle materials. Within lysosomes, acid ceramidase breaks down fats called ceramides into a fat called sphingosine and a fatty acid. These two breakdown products are recycled to create new ceramides for the body to use. Ceramides have several roles within cells. For example, they are a component of a fatty substance called myelin that insulates and protects nerve cells. ASAH1 gene mutations that cause SMA-PME result in a reduction of acid ceramidase activity to a level less than one-third of normal. Inefficient breakdown of ceramides and impaired production of its breakdown products likely play a role in the nerve cell damage that leads to the features of SMA-PME, but the exact mechanism is unknown. | spinal muscular atrophy with progressive myoclonic epilepsy |
Is spinal muscular atrophy with progressive myoclonic epilepsy 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. | spinal muscular atrophy with progressive myoclonic epilepsy |
What are the treatments for spinal muscular atrophy with progressive myoclonic epilepsy ? | These resources address the diagnosis or management of spinal muscular atrophy with progressive myoclonic epilepsy: - Genetic Testing Registry: Jankovic Rivera syndrome - Muscular Dystrophy Association: Spinal Muscular Atrophy Types 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 | spinal muscular atrophy with progressive myoclonic epilepsy |
What is (are) epidermolysis bullosa simplex ? | Epidermolysis bullosa simplex is one of a group of genetic conditions called epidermolysis bullosa that cause the skin to be very fragile and to blister easily. Blisters and areas of skin loss (erosions) occur in response to minor injury or friction, such as rubbing or scratching. Epidermolysis bullosa simplex is one of the major forms of epidermolysis bullosa. The signs and symptoms of this condition vary widely among affected individuals. Blistering primarily affects the hands and feet in mild cases, and the blisters usually heal without leaving scars. Severe cases of this condition involve widespread blistering that can lead to infections, dehydration, and other medical problems. Severe cases may be life-threatening in infancy. Researchers have identified four major types of epidermolysis bullosa simplex. Although the types differ in severity, their features overlap significantly, and they are caused by mutations in the same genes. Most researchers now consider the major forms of this condition to be part of a single disorder with a range of signs and symptoms. The mildest form of epidermolysis bullosa simplex, known as the localized type (formerly called the Weber-Cockayne type), is characterized by skin blistering that begins anytime between childhood and adulthood and is usually limited to the hands and feet. Later in life, skin on the palms of the hands and soles of the feet may thicken and harden (hyperkeratosis). The Dowling-Meara type is the most severe form of epidermolysis bullosa simplex. Extensive, severe blistering can occur anywhere on the body, including the inside of the mouth, and blisters may appear in clusters. Blistering is present from birth and tends to improve with age. Affected individuals also experience abnormal nail growth and hyperkeratosis of the palms and soles. Another form of epidermolysis bullosa simplex, known as the other generalized type (formerly called the Koebner type), is associated with widespread blisters that appear at birth or in early infancy. The blistering tends to be less severe than in the Dowling-Meara type. Epidermolysis bullosa simplex with mottled pigmentation is characterized by patches of darker skin on the trunk, arms, and legs that fade in adulthood. This form of the disorder also involves skin blistering from early infancy, hyperkeratosis of the palms and soles, and abnormal nail growth. In addition to the four major types described above, researchers have identified another skin condition related to epidermolysis bullosa simplex, which they call the Ogna type. It is caused by mutations in a gene that is not associated with the other types of epidermolysis bullosa simplex. It is unclear whether the Ogna type is a subtype of epidermolysis bullosa simplex or represents a separate form of epidermolysis bullosa. Several other variants of epidermolysis bullosa simplex have been proposed, but they appear to be very rare. | epidermolysis bullosa simplex |
How many people are affected by epidermolysis bullosa simplex ? | The exact prevalence of epidermolysis bullosa simplex is unknown, but this condition is estimated to affect 1 in 30,000 to 50,000 people. The localized type is the most common form of the condition. | epidermolysis bullosa simplex |
What are the genetic changes related to epidermolysis bullosa simplex ? | The four major types of epidermolysis bullosa simplex can result from mutations in either the KRT5 or KRT14 gene. These genes provide instructions for making proteins called keratin 5 and keratin 14. These tough, fibrous proteins work together to provide strength and resiliency to the outer layer of the skin (the epidermis). Mutations in either the KRT5 or KRT14 gene prevent the keratin proteins from assembling into strong networks, causing cells in the epidermis to become fragile and easily damaged. As a result, the skin is less resistant to friction and minor trauma and blisters easily. In rare cases, no KRT5 or KRT14 gene mutations are identified in people with one of the four major types of epidermolysis bullosa simplex. Mutations in another gene, PLEC, have been associated with the rare Ogna type of epidermolysis bullosa simplex. The PLEC gene provides instructions for making a protein called plectin, which helps attach the epidermis to underlying layers of skin. Researchers are working to determine how PLEC gene mutations lead to the major features of the condition. | epidermolysis bullosa simplex |
Is epidermolysis bullosa simplex inherited ? | Epidermolysis bullosa simplex is usually inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Some affected people inherit the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family. In rare cases, epidermolysis bullosa simplex is inherited in an autosomal recessive pattern. Autosomal recessive inheritance means the condition results when two copies of the gene in each cell are altered. The parents of an individual with an autosomal recessive disorder typically each carry one copy of the altered gene, but do not show signs and symptoms of the disorder. | epidermolysis bullosa simplex |
What are the treatments for epidermolysis bullosa simplex ? | These resources address the diagnosis or management of epidermolysis bullosa simplex: - Dystrophic Epidermolysis Bullosa Research Association (DebRA) of America: Wound Care - Epidermolysis Bullosa Center, Cincinnati Children's Hospital Medical Center - Gene Review: Gene Review: Epidermolysis Bullosa Simplex - Genetic Testing Registry: Epidermolysis bullosa simplex - Genetic Testing Registry: Epidermolysis bullosa simplex with mottled pigmentation - Genetic Testing Registry: Epidermolysis bullosa simplex, Cockayne-Touraine type - Genetic Testing Registry: Epidermolysis bullosa simplex, Koebner type - Genetic Testing Registry: Epidermolysis bullosa simplex, Ogna type - Genetic Testing Registry: Epidermolysis bullosa simplex, autosomal recessive - MedlinePlus Encyclopedia: Epidermolysis Bullosa 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 | epidermolysis bullosa simplex |
What is (are) ring chromosome 14 syndrome ? | Ring chromosome 14 syndrome is a condition characterized by seizures and intellectual disability. Recurrent seizures (epilepsy) develop in infancy or early childhood. In many cases, the seizures are resistant to treatment with anti-epileptic drugs. Most people with ring chromosome 14 syndrome also have some degree of intellectual disability or learning problems. Development may be delayed, particularly the development of speech and of motor skills such as sitting, standing, and walking. Additional features of ring chromosome 14 syndrome can include slow growth and short stature, a small head (microcephaly), puffy hands and/or feet caused by a buildup of fluid (lymphedema), and subtle differences in facial features. Some affected individuals have problems with their immune system that lead to recurrent infections, especially involving the respiratory system. Abnormalities of the retina, the specialized tissue at the back of the eye that detects light and color, have also been reported in some people with this condition. These changes typically do not affect vision. Major birth defects are rarely seen with ring chromosome 14 syndrome. | ring chromosome 14 syndrome |
How many people are affected by ring chromosome 14 syndrome ? | Ring chromosome 14 syndrome appears to be a rare condition, although its prevalence is unknown. More than 50 affected individuals have been reported in the medical literature. | ring chromosome 14 syndrome |
What are the genetic changes related to ring chromosome 14 syndrome ? | Ring chromosome 14 syndrome is caused by a chromosomal abnormality known as a ring chromosome 14, sometimes written as r(14). A ring chromosome is a circular structure that occurs when a chromosome breaks in two places and its broken ends fuse together. People with ring chromosome 14 syndrome have one copy of this abnormal chromosome in some or all of their cells. Researchers believe that several critical genes near the end of the long (q) arm of chromosome 14 are lost when the ring chromosome forms. The loss of these genes is likely responsible for several of the major features of ring chromosome 14 syndrome, including intellectual disability and delayed development. Researchers are still working to determine which missing genes contribute to the signs and symptoms of this disorder. Epilepsy is a common feature of ring chromosome syndromes, including ring chromosome 14. There may be something about the ring structure itself that causes epilepsy. Seizures may occur because certain genes on the ring chromosome 14 are less active than those on the normal chromosome 14. Alternately, seizures might result from instability of the ring chromosome in some cells. | ring chromosome 14 syndrome |
Is ring chromosome 14 syndrome inherited ? | Ring chromosome 14 syndrome is almost never inherited. A ring chromosome typically occurs as a random event during the formation of reproductive cells (eggs or sperm) or in early embryonic development. In some cases, the ring chromosome is present in only some of a person's cells. This situation is known as mosaicism. Most affected individuals have no history of the disorder in their families. However, at least two families have been reported in which a ring chromosome 14 was passed from a mother to her children. | ring chromosome 14 syndrome |
What are the treatments for ring chromosome 14 syndrome ? | These resources address the diagnosis or management of ring chromosome 14 syndrome: - Genetic Testing Registry: Ring chromosome 14 - MedlinePlus Encyclopedia: Chromosome 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 | ring chromosome 14 syndrome |
What is (are) spondylocarpotarsal synostosis syndrome ? | Spondylocarpotarsal synostosis syndrome is a disorder that affects the development of bones throughout the body. Newborns with this disorder are of approximately normal length, but impaired growth of the trunk results in short stature over time. The bones of the spine (vertebrae) are misshapen and abnormally joined together (fused). The vertebral abnormalities may result in an abnormally curved lower back (lordosis) and a spine that curves to the side (scoliosis). Affected individuals also have abnormalities of the wrist (carpal) and ankle (tarsal) bones and inward- and upward-turning feet (clubfeet). Characteristic facial features include a round face, a large forehead (frontal bossing), and nostrils that open to the front rather than downward (anteverted nares). Some people with spondylocarpotarsal synostosis syndrome have an opening in the roof of the mouth (a cleft palate), hearing loss, thin tooth enamel, flat feet, or an unusually large range of joint movement (hypermobility). Individuals with this disorder can survive into adulthood. Intelligence is generally unaffected, although mild developmental delay has been reported in some affected individuals. | spondylocarpotarsal synostosis syndrome |
How many people are affected by spondylocarpotarsal synostosis syndrome ? | Spondylocarpotarsal synostosis syndrome is a rare disorder; its prevalence is unknown. At least 25 affected individuals have been identified. | spondylocarpotarsal synostosis syndrome |
What are the genetic changes related to spondylocarpotarsal synostosis syndrome ? | Mutations in the FLNB gene cause spondylocarpotarsal synostosis syndrome. The FLNB gene provides instructions for making a protein called filamin B. This protein helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Filamin B attaches (binds) to another protein called actin and helps the actin to form the branching network of filaments that makes up the cytoskeleton. It also links actin to many other proteins to perform various functions within the cell, including the cell signaling that helps determine how the cytoskeleton will change as tissues grow and take shape during development. Filamin B is especially important in the development of the skeleton before birth. It is active (expressed) in the cell membranes of cartilage-forming cells (chondrocytes). Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone (a process called ossification), except for the cartilage that continues to cover and protect the ends of bones and is present in the nose, airways (trachea and bronchi), and external ears. Filamin B appears to be important for normal cell growth and division (proliferation) and maturation (differentiation) of chondrocytes and for the ossification of cartilage. FLNB gene mutations that cause spondylocarpotarsal synostosis syndrome result in the production of an abnormally short filamin B protein that is unstable and breaks down rapidly. Loss of the filamin B protein appears to result in out-of-place (ectopic) ossification, resulting in fusion of the bones in the spine, wrists, and ankles and other signs and symptoms of spondylocarpotarsal synostosis syndrome. A few individuals who have been diagnosed with spondylocarpotarsal synostosis syndrome do not have mutations in the FLNB gene. In these cases, the genetic cause of the disorder is unknown. | spondylocarpotarsal synostosis syndrome |
Is spondylocarpotarsal synostosis syndrome inherited ? | Spondylocarpotarsal synostosis syndrome caused by FLNB gene mutations 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. In a few individuals with signs and symptoms similar to those of spondylocarpotarsal synostosis syndrome but without FLNB gene mutations, the condition appears to have been inherited in an autosomal dominant pattern. Autosomal dominant means one copy of the altered gene in each cell is sufficient to cause the disorder. | spondylocarpotarsal synostosis syndrome |
What are the treatments for spondylocarpotarsal synostosis syndrome ? | These resources address the diagnosis or management of spondylocarpotarsal synostosis syndrome: - Gene Review: Gene Review: FLNB-Related Disorders - Genetic Testing Registry: Spondylocarpotarsal synostosis syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | spondylocarpotarsal synostosis syndrome |
What is (are) Axenfeld-Rieger syndrome ? | Axenfeld-Rieger syndrome is primarily an eye disorder, although it can also affect other parts of the body. This condition is characterized by abnormalities of the front part of the eye, an area known as the anterior segment. For example, the colored part of the eye (the iris), may be thin or poorly developed. The iris normally has a single central hole, called the pupil, through which light enters the eye. People with Axenfeld-Rieger syndrome often have a pupil that is off-center (corectopia) or extra holes in the iris that can look like multiple pupils (polycoria). This condition can also cause abnormalities of the cornea, which is the clear front covering of the eye. About half of affected individuals develop glaucoma, a serious condition that increases pressure inside the eye. When glaucoma occurs with Axenfeld-Rieger syndrome, it most often develops in late childhood or adolescence, although it can occur as early as infancy. Glaucoma can cause vision loss or blindness. The signs and symptoms of Axenfeld-Rieger syndrome can also affect other parts of the body. Many affected individuals have distinctive facial features such as widely spaced eyes (hypertelorism); a flattened mid-face with a broad, flat nasal bridge; and a prominent forehead. The condition is also associated with dental abnormalities including unusually small teeth (microdontia) or fewer than normal teeth (oligodontia). Some people with Axenfeld-Rieger syndrome have extra folds of skin around their belly button (redundant periumbilical skin). Other, less common features can include heart defects, the opening of the urethra on the underside of the penis (hypospadias), narrowing of the anus (anal stenosis), and abnormalities of the pituitary gland that can result in slow growth. Researchers have described at least three types of Axenfeld-Rieger syndrome. The types, which are numbered 1 through 3, are distinguished by their genetic cause. | Axenfeld-Rieger syndrome |
How many people are affected by Axenfeld-Rieger syndrome ? | Axenfeld-Rieger syndrome has an estimated prevalence of 1 in 200,000 people. | Axenfeld-Rieger syndrome |
What are the genetic changes related to Axenfeld-Rieger syndrome ? | Axenfeld-Rieger syndrome results from mutations in at least two known genes, PITX2 and FOXC1. PITX2 gene mutations cause type 1, and FOXC1 gene mutations cause type 3. The gene associated with type 2 is likely located on chromosome 13, but it has not been identified. The proteins produced from the PITX2 and FOXC1 genes are transcription factors, which means they attach (bind) to DNA and help control the activity of other genes. These transcription factors are active before birth in the developing eye and in other parts of the body. They appear to play important roles in embryonic development, particularly in the formation of structures in the anterior segment of the eye. Mutations in either the PITX2 or FOXC1 gene disrupt the activity of other genes that are needed for normal development. Impaired regulation of these genes leads to problems in the formation of the anterior segment of the eye and other parts of the body. These developmental abnormalities underlie the characteristic features of Axenfeld-Rieger syndrome. Affected individuals with PITX2 gene mutations are more likely than those with FOXC1 gene mutations to have abnormalities affecting parts of the body other than the eye. Some people with Axenfeld-Rieger syndrome do not have identified mutations in the PITX2 or FOXC1 genes. In these individuals, the cause of the condition is unknown. Other as-yet-unidentified genes may also cause Axenfeld-Rieger syndrome. | Axenfeld-Rieger syndrome |
Is Axenfeld-Rieger 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. | Axenfeld-Rieger syndrome |
What are the treatments for Axenfeld-Rieger syndrome ? | These resources address the diagnosis or management of Axenfeld-Rieger syndrome: - Genetic Testing Registry: Axenfeld-Rieger syndrome type 1 - Genetic Testing Registry: Axenfeld-Rieger syndrome type 2 - Genetic Testing Registry: Axenfeld-Rieger syndrome type 3 - Genetic Testing Registry: Rieger syndrome - Glaucoma Research Foundation: Care and Treatment 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 | Axenfeld-Rieger syndrome |
What is (are) cystinosis ? | Cystinosis is a condition characterized by accumulation of the amino acid cystine (a building block of proteins) within cells. Excess cystine damages cells and often forms crystals that can build up and cause problems in many organs and tissues. The kidneys and eyes are especially vulnerable to damage; the muscles, thyroid, pancreas, and testes may also be affected. There are three distinct types of cystinosis. In order of decreasing severity, they are nephropathic cystinosis, intermediate cystinosis, and non-nephropathic or ocular cystinosis. Nephropathic cystinosis begins in infancy, causing poor growth and a particular type of kidney damage (renal Fanconi syndrome) in which certain molecules that should be reabsorbed into the bloodstream are instead eliminated in the urine. The kidney problems lead to the loss of important minerals, salts, fluids, and many other nutrients. The loss of nutrients impairs growth and may result in soft, bowed bones (hypophosphatemic rickets), especially in the legs. The nutrient imbalances in the body lead to increased urination, thirst, dehydration, and abnormally acidic blood (acidosis). By about the age of 2, cystine crystals may be present in the clear covering of the eye (cornea). The buildup of these crystals in the eye causes pain and an increased sensitivity to light (photophobia). Untreated children will experience complete kidney failure by about the age of 10. Other signs and symptoms that may occur in untreated people, especially after adolescence, include muscle deterioration, blindness, inability to swallow, diabetes, thyroid and nervous system problems, and an inability to father children (infertility) in affected men. The signs and symptoms of intermediate cystinosis are the same as nephropathic cystinosis, but they occur at a later age. Intermediate cystinosis typically becomes apparent in affected individuals in adolescence. Malfunctioning kidneys and corneal crystals are the main initial features of this disorder. If intermediate cystinosis is left untreated, complete kidney failure will occur, but usually not until the late teens to mid-twenties. People with non-nephropathic or ocular cystinosis typically experience photophobia due to cystine crystals in the cornea, but usually do not develop kidney malfunction or most of the other signs and symptoms of cystinosis. Due to the absence of severe symptoms, the age at which this form of cystinosis is diagnosed varies widely. | cystinosis |
How many people are affected by cystinosis ? | Cystinosis affects approximately 1 in 100,000 to 200,000 newborns worldwide. The incidence is higher in the province of Brittany, France, where the disorder affects 1 in 26,000 individuals. | cystinosis |
What are the genetic changes related to cystinosis ? | All three types of cystinosis are caused by mutations in the CTNS gene. Mutations in this gene lead to a deficiency of a transporter protein called cystinosin. Within cells, this protein normally moves cystine out of the lysosomes, which are compartments in the cell that digest and recycle materials. When cystinosin is defective or missing, cystine accumulates and forms crystals in the lysosomes. The buildup of cystine damages cells in the kidneys and eyes and may also affect other organs. | cystinosis |
Is cystinosis 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. | cystinosis |
What are the treatments for cystinosis ? | These resources address the diagnosis or management of cystinosis: - Cystinosis Research Foundation: Treatment - Cystinosis Research Network: Symptoms and Treatment - Gene Review: Gene Review: Cystinosis - Genetic Testing Registry: Cystinosis - Genetic Testing Registry: Cystinosis, ocular nonnephropathic - Genetic Testing Registry: Juvenile nephropathic cystinosis - MedlinePlus Encyclopedia: Fanconi Syndrome - MedlinePlus Encyclopedia: Photophobia 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 | cystinosis |
What is (are) inclusion body myopathy with early-onset Paget disease and frontotemporal dementia ? | Inclusion body myopathy with early-onset Paget disease and frontotemporal dementia (IBMPFD) is a condition that can affect the muscles, bones, and brain. The first symptom of IBMPFD is often muscle weakness (myopathy), which typically appears in mid-adulthood. Weakness first occurs in muscles of the hips and shoulders, making it difficult to climb stairs and raise the arms above the shoulders. As the disorder progresses, weakness develops in other muscles in the arms and legs. Muscle weakness can also affect respiratory and heart (cardiac) muscles, leading to life-threatening breathing difficulties and heart failure. About half of all adults with IBMPFD develop a disorder called Paget disease of bone. This disorder most often affects bones of the hips, spine, and skull, and the long bones of the arms and legs. Bone pain, particularly in the hips and spine, is usually the major symptom of Paget disease. Rarely, this condition can weaken bones so much that they break (fracture). In about one-third of people with IBMPFD, the disorder also affects the brain. IBMPFD is associated with a brain condition called frontotemporal dementia, which becomes noticeable in a person's forties or fifties. Frontotemporal dementia progressively damages parts of the brain that control reasoning, personality, social skills, speech, and language. People with this condition initially may have trouble speaking, remembering words and names (dysnomia), and using numbers (dyscalculia). Personality changes, a loss of judgment, and inappropriate social behavior are also hallmarks of the disease. As the dementia worsens, affected people ultimately become unable to speak, read, or care for themselves. People with IBMPFD usually live into their fifties or sixties. | inclusion body myopathy with early-onset Paget disease and frontotemporal dementia |
How many people are affected by inclusion body myopathy with early-onset Paget disease and frontotemporal dementia ? | Although the prevalence of IBMPFD is unknown, this condition is rare. It has been identified in about 26 families. | inclusion body myopathy with early-onset Paget disease and frontotemporal dementia |
What are the genetic changes related to inclusion body myopathy with early-onset Paget disease and frontotemporal dementia ? | Mutations in the VCP gene cause IBMPFD. The VCP gene provides instructions for making an enzyme called valosin-containing protein, which has a wide variety of functions within cells. One of its most critical jobs is to help break down (degrade) proteins that are abnormal or no longer needed. Mutations in the VCP gene alter the structure of valosin-containing protein, disrupting its ability to break down other proteins. As a result, excess and abnormal proteins may build up in muscle, bone, and brain cells. The proteins form clumps that interfere with the normal functions of these cells. It remains unclear how damage to muscle, bone, and brain cells leads to the specific features of IBMPFD. | inclusion body myopathy with early-onset Paget disease and frontotemporal dementia |
Is inclusion body myopathy with early-onset Paget disease and frontotemporal dementia inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family. | inclusion body myopathy with early-onset Paget disease and frontotemporal dementia |
What are the treatments for inclusion body myopathy with early-onset Paget disease and frontotemporal dementia ? | These resources address the diagnosis or management of IBMPFD: - Gene Review: Gene Review: Inclusion Body Myopathy with Paget Disease of Bone and/or Frontotemporal Dementia - Genetic Testing Registry: Inclusion body myopathy with early-onset paget disease and frontotemporal dementia These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | inclusion body myopathy with early-onset Paget disease and frontotemporal dementia |
What is (are) tuberous sclerosis complex ? | Tuberous sclerosis complex is a genetic disorder characterized by the growth of numerous noncancerous (benign) tumors in many parts of the body. These tumors can occur in the skin, brain, kidneys, and other organs, in some cases leading to significant health problems. Tuberous sclerosis complex also causes developmental problems, and the signs and symptoms of the condition vary from person to person. Virtually all affected people have skin abnormalities, including patches of unusually light-colored skin, areas of raised and thickened skin, and growths under the nails. Tumors on the face called facial angiofibromas are also common beginning in childhood. Tuberous sclerosis complex often affects the brain, causing seizures, behavioral problems such as hyperactivity and aggression, and intellectual disability or learning problems. Some affected children have the characteristic features of autism, a developmental disorder that affects communication and social interaction. Benign brain tumors can also develop in people with tuberous sclerosis complex; these tumors can cause serious or life-threatening complications. Kidney tumors are common in people with tuberous sclerosis complex; these growths can cause severe problems with kidney function and may be life-threatening in some cases. Additionally, tumors can develop in the heart, lungs, and the light-sensitive tissue at the back of the eye (the retina). | tuberous sclerosis complex |
How many people are affected by tuberous sclerosis complex ? | Tuberous sclerosis complex affects about 1 in 6,000 people. | tuberous sclerosis complex |
What are the genetic changes related to tuberous sclerosis complex ? | Mutations in the TSC1 or TSC2 gene can cause tuberous sclerosis complex. The TSC1 and TSC2 genes provide instructions for making the proteins hamartin and tuberin, respectively. Within cells, these two proteins likely work together to help regulate cell growth and size. The proteins act as tumor suppressors, which normally prevent cells from growing and dividing too fast or in an uncontrolled way. People with tuberous sclerosis complex are born with one mutated copy of the TSC1 or TSC2 gene in each cell. This mutation prevents the cell from making functional hamartin or tuberin from the altered copy of the gene. However, enough protein is usually produced from the other, normal copy of the gene to regulate cell growth effectively. For some types of tumors to develop, a second mutation involving the other copy of the TSC1 or TSC2 gene must occur in certain cells during a person's lifetime. When both copies of the TSC1 gene are mutated in a particular cell, that cell cannot produce any functional hamartin; cells with two altered copies of the TSC2 gene are unable to produce any functional tuberin. The loss of these proteins allows the cell to grow and divide in an uncontrolled way to form a tumor. In people with tuberous sclerosis complex, a second TSC1 or TSC2 mutation typically occurs in multiple cells over an affected person's lifetime. The loss of hamartin or tuberin in different types of cells leads to the growth of tumors in many different organs and tissues. | tuberous sclerosis complex |
Is tuberous sclerosis complex inherited ? | Tuberous sclerosis complex has an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to increase the risk of developing tumors and other problems with development. In about one-third of cases, an affected person inherits an altered TSC1 or TSC2 gene from a parent who has the disorder. The remaining two-thirds of people with tuberous sclerosis complex are born with new mutations in the TSC1 or TSC2 gene. These cases, which are described as sporadic, occur in people with no history of tuberous sclerosis complex in their family. TSC1 mutations appear to be more common in familial cases of tuberous sclerosis complex, while mutations in the TSC2 gene occur more frequently in sporadic cases. | tuberous sclerosis complex |
What are the treatments for tuberous sclerosis complex ? | These resources address the diagnosis or management of tuberous sclerosis complex: - Gene Review: Gene Review: Tuberous Sclerosis Complex - Genetic Testing Registry: Tuberous sclerosis syndrome - MedlinePlus Encyclopedia: Tuberous Sclerosis - Tuberous Sclerosis Alliance: TSC Clinics 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 | tuberous sclerosis complex |
What is (are) nonsyndromic aplasia cutis congenita ? | Nonsyndromic aplasia cutis congenita is a condition in which babies are born with localized areas of missing skin (lesions). These areas resemble ulcers or open wounds, although they are sometimes already healed at birth. Lesions most commonly occur on the top of the head (skull vertex), although they can be found on the torso or limbs. In some cases, the bone and other tissues under the skin defect are also underdeveloped. Most affected babies have a single lesion. The lesions vary in size and can be differently shaped: some are round or oval, others rectangular, and still others star-shaped. They usually leave a scar after they heal. When the scalp is involved, there may be an absence of hair growth (alopecia) in the affected area. When the underlying bone and other tissues are involved, affected individuals are at higher risk of infections. If these severe defects occur on the head, the membrane that covers the brain (the dura mater) may be exposed, and life-threatening bleeding may occur from nearby vessels. Skin lesions are typically the only feature of nonsyndromic aplasia cutis congenita, although other skin problems and abnormalities of the bones and other tissues occur rarely. However, the characteristic skin lesions can occur as one of many symptoms in other conditions, including Johanson-Blizzard syndrome and Adams-Oliver syndrome. These instances are described as syndromic aplasia cutis congenita. | nonsyndromic aplasia cutis congenita |
How many people are affected by nonsyndromic aplasia cutis congenita ? | Aplasia cutis congenita affects approximately 1 in 10,000 newborns. The incidence of the nonsyndromic form is unknown. | nonsyndromic aplasia cutis congenita |
What are the genetic changes related to nonsyndromic aplasia cutis congenita ? | Nonsyndromic aplasia cutis congenita can have different causes, and often the cause is unknown. Because the condition is sometimes found in multiple members of a family, it is thought to have a genetic component; however, the genetic factors are not fully understood. Researchers suggest that genes important for skin growth may be involved. It is thought that impairments of skin growth more commonly affect the skin at the top of the head because that region needs to be able to grow quickly to cover the fast-growing skull of a developing baby. In some cases, nonsyndromic aplasia cutis congenita is caused by exposure to a drug called methimazole before birth. This medication is given to treat an overactive thyroid gland. Babies whose mothers take this medication during pregnancy are at increased risk of having the condition. In addition, certain viral infections in a pregnant mother can cause the baby to be born with the skin lesions characteristic of nonsyndromic aplasia cutis congenita. Other cases are thought to be caused by injury to the baby during development. | nonsyndromic aplasia cutis congenita |
Is nonsyndromic aplasia cutis congenita inherited ? | Most cases of nonsyndromic aplasia cutis congenita are sporadic, which means they occur in people with no history of the disorder in their family. When the condition runs in families, inheritance usually follows an autosomal dominant pattern, which means one copy of an altered gene in each cell is sufficient to cause the disorder. Rarely, the condition appears to follow 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 typically do not show signs and symptoms of the condition. | nonsyndromic aplasia cutis congenita |
What are the treatments for nonsyndromic aplasia cutis congenita ? | These resources address the diagnosis or management of nonsyndromic aplasia cutis congenita: - Genetic Testing Registry: Aplasia cutis congenita 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 aplasia cutis congenita |
What is (are) Kearns-Sayre syndrome ? | Kearns-Sayre syndrome is a condition that affects many parts of the body, especially the eyes. The features of Kearns-Sayre syndrome usually appear before age 20, and the condition is diagnosed by a few characteristic signs and symptoms. People with Kearns-Sayre syndrome have progressive external ophthalmoplegia, which is weakness or paralysis of the eye muscles that impairs eye movement and causes drooping eyelids (ptosis). Affected individuals also have an eye condition called pigmentary retinopathy, which results from breakdown (degeneration) of the light-sensing tissue at the back of the eye (the retina) that gives it a speckled and streaked appearance. The retinopathy may cause loss of vision. In addition, people with Kearns-Sayre syndrome have at least one of the following signs or symptoms: abnormalities of the electrical signals that control the heartbeat (cardiac conduction defects), problems with coordination and balance that cause unsteadiness while walking (ataxia), or abnormally high levels of protein in the fluid that surrounds and protects the brain and spinal cord (the cerebrospinal fluid or CSF). People with Kearns-Sayre syndrome may also experience muscle weakness in their limbs, deafness, kidney problems, or a deterioration of cognitive functions (dementia). Affected individuals often have short stature. In addition, diabetes mellitus is occasionally seen in people with Kearns-Sayre syndrome. When the muscle cells of affected individuals are stained and viewed under a microscope, these cells usually appear abnormal. The abnormal muscle cells contain an excess of structures called mitochondria and are known as ragged-red fibers. A related condition called ophthalmoplegia-plus may be diagnosed if an individual has many of the signs and symptoms of Kearns-Sayre syndrome but not all the criteria are met. | Kearns-Sayre syndrome |
How many people are affected by Kearns-Sayre syndrome ? | The prevalence of Kearns-Sayre syndrome is approximately 1 to 3 per 100,000 individuals. | Kearns-Sayre syndrome |
What are the genetic changes related to Kearns-Sayre syndrome ? | Kearns-Sayre syndrome is a condition caused by defects in mitochondria, which are structures within cells that use oxygen to convert the energy from food into a form cells can use. This process is called oxidative phosphorylation. Although most DNA is packaged in chromosomes within the nucleus (nuclear DNA), mitochondria also have a small amount of their own DNA, called mitochondrial DNA (mtDNA). This type of DNA contains many genes essential for normal mitochondrial function. People with Kearns-Sayre syndrome have a single, large deletion of mtDNA, ranging from 1,000 to 10,000 DNA building blocks (nucleotides). The cause of the deletion in affected individuals is unknown. The mtDNA deletions that cause Kearns-Sayre syndrome result in the loss of genes important for mitochondrial protein formation and oxidative phosphorylation. The most common deletion removes 4,997 nucleotides, which includes twelve mitochondrial genes. Deletions of mtDNA result in impairment of oxidative phosphorylation and a decrease in cellular energy production. Regardless of which genes are deleted, all steps of oxidative phosphorylation are affected. Researchers have not determined how these deletions lead to the specific signs and symptoms of Kearns-Sayre syndrome, although the features of the condition are probably related to a lack of cellular energy. It has been suggested that eyes are commonly affected by mitochondrial defects because they are especially dependent on mitochondria for energy. | Kearns-Sayre syndrome |
Is Kearns-Sayre syndrome inherited ? | This condition is generally not inherited but arises from mutations in the body's cells that occur after conception. This alteration is called a somatic mutation and is present only in certain cells. Rarely, this condition is inherited in a mitochondrial pattern, which is also known as maternal inheritance. This pattern of inheritance applies to genes contained in mtDNA. Because egg cells, but not sperm cells, contribute mitochondria to the developing embryo, children can only inherit disorders resulting from mtDNA mutations from their mother. These disorders can appear in every generation of a family and can affect both males and females, but fathers do not pass traits associated with changes in mtDNA to their children. | Kearns-Sayre syndrome |
What are the treatments for Kearns-Sayre syndrome ? | These resources address the diagnosis or management of Kearns-Sayre syndrome: - Gene Review: Gene Review: Mitochondrial DNA Deletion Syndromes - Genetic Testing Registry: Kearns Sayre syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Kearns-Sayre syndrome |
What is (are) hypohidrotic ectodermal dysplasia ? | Hypohidrotic ectodermal dysplasia is one of about 150 types of ectodermal dysplasia in humans. Before birth, these disorders result in the abnormal development of structures including the skin, hair, nails, teeth, and sweat glands. Most people with hypohidrotic ectodermal dysplasia have a reduced ability to sweat (hypohidrosis) because they have fewer sweat glands than normal or their sweat glands do not function properly. Sweating is a major way that the body controls its temperature; as sweat evaporates from the skin, it cools the body. An inability to sweat can lead to a dangerously high body temperature (hyperthermia), particularly in hot weather. In some cases, hyperthermia can cause life-threatening medical problems. Affected individuals tend to have sparse scalp and body hair (hypotrichosis). The hair is often light-colored, brittle, and slow-growing. This condition is also characterized by absent teeth (hypodontia) or teeth that are malformed. The teeth that are present are frequently small and pointed. Hypohidrotic ectodermal dysplasia is associated with distinctive facial features including a prominent forehead, thick lips, and a flattened bridge of the nose. Additional features of this condition include thin, wrinkled, and dark-colored skin around the eyes; chronic skin problems such as eczema; and a bad-smelling discharge from the nose (ozena). | hypohidrotic ectodermal dysplasia |
How many people are affected by hypohidrotic ectodermal dysplasia ? | Hypohidrotic ectodermal dysplasia is the most common form of ectodermal dysplasia in humans. It is estimated to affect at least 1 in 17,000 people worldwide. | hypohidrotic ectodermal dysplasia |
What are the genetic changes related to hypohidrotic ectodermal dysplasia ? | Mutations in the EDA, EDAR, and EDARADD genes cause hypohidrotic ectodermal dysplasia. The EDA, EDAR, and EDARADD genes provide instructions for making proteins that work together during embryonic development. These proteins form part of a signaling pathway that is critical for the interaction between two cell layers, the ectoderm and the mesoderm. In the early embryo, these cell layers form the basis for many of the body's organs and tissues. Ectoderm-mesoderm interactions are essential for the formation of several structures that arise from the ectoderm, including the skin, hair, nails, teeth, and sweat glands. Mutations in the EDA, EDAR, or EDARADD gene prevent normal interactions between the ectoderm and the mesoderm and impair the normal development of hair, sweat glands, and teeth. The improper formation of these ectodermal structures leads to the characteristic features of hypohidrotic ectodermal dysplasia. | hypohidrotic ectodermal dysplasia |
Is hypohidrotic ectodermal dysplasia inherited ? | Hypohidrotic ectodermal dysplasia has several different inheritance patterns. Most cases are caused by mutations in the EDA gene, which are inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the disorder. Males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. In about 70 percent of cases, carriers of hypohidrotic ectodermal dysplasia experience some features of the condition. These signs and symptoms are usually mild and include a few missing or abnormal teeth, sparse hair, and some problems with sweat gland function. Some carriers, however, have more severe features of this disorder. Less commonly, hypohidrotic ectodermal dysplasia results from mutations in the EDAR or EDARADD gene. EDAR mutations can have an autosomal dominant or autosomal recessive pattern of inheritance, and EDARADD mutations have an autosomal recessive pattern of inheritance. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder. Autosomal recessive inheritance means two copies of the gene in each cell are altered. Most often, the parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene but do not show signs and symptoms of the disorder. | hypohidrotic ectodermal dysplasia |
What are the treatments for hypohidrotic ectodermal dysplasia ? | These resources address the diagnosis or management of hypohidrotic ectodermal dysplasia: - Gene Review: Gene Review: Hypohidrotic Ectodermal Dysplasia - Genetic Testing Registry: Autosomal dominant hypohidrotic ectodermal dysplasia - Genetic Testing Registry: Autosomal recessive hypohidrotic ectodermal dysplasia syndrome - Genetic Testing Registry: Hypohidrotic X-linked ectodermal dysplasia - MedlinePlus Encyclopedia: Ectodermal dysplasia - MedlinePlus Encyclopedia: Ozena - MedlinePlus Encyclopedia: Sweating - absent These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | hypohidrotic ectodermal dysplasia |
What is (are) dermatofibrosarcoma protuberans ? | Dermatofibrosarcoma protuberans is a rare type of cancer that causes a tumor in the deep layers of skin. This condition is a type of soft tissue sarcoma, which are cancers that affect skin, fat, muscle, and similar tissues. In dermatofibrosarcoma protuberans, the tumor most often starts as a small, firm patch of skin, usually 1 to 5 centimeters in diameter, that is usually purplish, reddish, or flesh-colored. The tumor typically grows slowly and can become a raised nodule. Occasionally, the tumor begins as a flat or depressed patch of skin (plaque). Tumors are most commonly found on the torso and can also be found on the arms, legs, head, or neck. Affected individuals usually first show signs of this condition in their thirties, but the age at which a tumor appears varies widely. In dermatofibrosarcoma protuberans, the tumor has a tendency to return after being removed. However, it does not often spread to other parts of the body (metastasize). There are several variants of dermatofibrosarcoma protuberans in which different cell types are involved in the tumor. Bednar tumors, often called pigmented dermatofibrosarcoma protuberans, contain dark-colored (pigmented) cells called melanin-containing dendritic cells. Myxoid dermatofibrosarcoma protuberans tumors contain an abnormal type of connective tissue known as myxoid stroma. Giant cell fibroblastoma, which is sometimes referred to as juvenile dermatofibrosarcoma protuberans because it typically affects children and adolescents, is characterized by giant cells in the tumor. Rarely, the tumors involved in the different types of dermatofibrosarcoma protuberans can have regions that look similar to fibrosarcoma, a more aggressive type of soft tissue sarcoma. In these cases, the condition is called fibrosarcomatous dermatofibrosarcoma protuberans or FS-DFSP. FS-DFSP tumors are more likely to metastasize than tumors in the other types of dermatofibrosarcoma protuberans. | dermatofibrosarcoma protuberans |
How many people are affected by dermatofibrosarcoma protuberans ? | Dermatofibrosarcoma protuberans is estimated to occur in 1 in 100,000 to 1 in 1 million people per year. | dermatofibrosarcoma protuberans |
What are the genetic changes related to dermatofibrosarcoma protuberans ? | Dermatofibrosarcoma protuberans is associated with a rearrangement (translocation) of genetic material between chromosomes 17 and 22. This translocation, written as t(17;22), fuses part of the COL1A1 gene from chromosome 17 with part of the PDGFB gene from chromosome 22. The translocation is found on one or more extra chromosomes that can be either the normal linear shape or circular. When circular, the extra chromosomes are known as supernumerary ring chromosomes. Ring chromosomes occur when a chromosome breaks in two places and the ends of the chromosome arms fuse together to form a circular structure. Other genes from chromosomes 17 and 22 can be found on the extra chromosomes, but the role these genes play in development of the condition is unclear. The translocation is acquired during a person's lifetime and the chromosomes containing the translocation are present only in the tumor cells. This type of genetic change is called a somatic mutation. In normal cells, the COL1A1 gene provides instructions for making part of a large molecule called type I collagen, which strengthens and supports many tissues in the body. The PDGFB gene provides instructions for making one version (isoform) of the platelet derived growth factor (PDGF) protein. By attaching to its receptor, the active PDGFB protein stimulates many cellular processes, including cell growth and division (proliferation) and maturation (differentiation). The abnormally fused COL1A1-PDGFB gene provides instructions for making an abnormal combined (fusion) protein that researchers believe ultimately functions like the PDGFB protein. The gene fusion leads to the production of an excessive amount of protein that functions like the PDGFB protein. In excess, this fusion protein stimulates cells to proliferate and differentiate abnormally, leading to the tumor formation seen in dermatofibrosarcoma protuberans. The COL1A1-PDGFB fusion gene is found in more than 90 percent of dermatofibrosarcoma protuberans cases. In the remaining cases, changes in other genes may be associated with this condition. These genes have not been identified. | dermatofibrosarcoma protuberans |
Is dermatofibrosarcoma protuberans inherited ? | Dermatofibrosarcoma protuberans results from a new mutation that occurs in the body's cells after conception and is found only in the tumor cells. This type of genetic change is called a somatic mutation and is generally not inherited. | dermatofibrosarcoma protuberans |
What are the treatments for dermatofibrosarcoma protuberans ? | These resources address the diagnosis or management of dermatofibrosarcoma protuberans: - American Cancer Society: How are Soft Tissue Sarcomas Diagnosed? - American Cancer Society: Treatment of Soft Tissue Sarcomas - Genetic Testing Registry: Dermatofibrosarcoma protuberans - National Cancer Institute: Adult Soft Tissue Sarcoma - National Cancer Institute: Targeted Cancer Therapies These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | dermatofibrosarcoma protuberans |
What is (are) Pitt-Hopkins syndrome ? | Pitt-Hopkins syndrome is a condition characterized by intellectual disability and developmental delay, breathing problems, recurrent seizures (epilepsy), and distinctive facial features. People with Pitt-Hopkins syndrome have moderate to severe intellectual disability. Most affected individuals have delayed development of mental and motor skills (psychomotor delay). They are delayed in learning to walk and developing fine motor skills such as picking up small items with their fingers. People with Pitt-Hopkins syndrome typically do not develop speech; some may learn to say a few words. Many affected individuals exhibit features of autistic spectrum disorders, which are characterized by impaired communication and socialization skills. Breathing problems in individuals with Pitt-Hopkins syndrome are characterized by episodes of rapid breathing (hyperventilation) followed by periods in which breathing slows or stops (apnea). These episodes can cause a lack of oxygen in the blood, leading to a bluish appearance of the skin or lips (cyanosis). In some cases, the lack of oxygen can cause loss of consciousness. Some older individuals with Pitt-Hopkins syndrome develop widened and rounded tips of the fingers and toes (clubbing) because of recurrent episodes of decreased oxygen in the blood. The breathing problems occur only when the person is awake and typically first appear in mid-childhood, but they can begin as early as infancy. Episodes of hyperventilation and apnea can be triggered by emotions such as excitement or anxiety or by extreme tiredness (fatigue). Epilepsy occurs in most people with Pitt-Hopkins syndrome and usually begins during childhood, although it can be present from birth. Individuals with Pitt-Hopkins syndrome have distinctive facial features that include thin eyebrows, sunken eyes, a prominent nose with a high nasal bridge, a pronounced double curve of the upper lip (Cupid's bow), a wide mouth with full lips, and widely spaced teeth. The ears are usually thick and cup-shaped. Children with Pitt-Hopkins syndrome typically have a happy, excitable demeanor with frequent smiling, laughter, and hand-flapping movements. However, they can also experience anxiety and behavioral problems. Other features of Pitt-Hopkins syndrome may include constipation and other gastrointestinal problems, an unusually small head (microcephaly), nearsightedness (myopia), eyes that do not look in the same direction (strabismus), short stature, and minor brain abnormalities. Affected individuals may also have small hands and feet, a single crease across the palms of the hands, flat feet (pes planus), or unusually fleshy pads at the tips of the fingers and toes. Males with Pitt-Hopkins syndrome may have undescended testes (cryptorchidism). | Pitt-Hopkins syndrome |
How many people are affected by Pitt-Hopkins syndrome ? | Pitt-Hopkins syndrome is thought to be a very rare condition. Approximately 500 affected individuals have been reported worldwide. | Pitt-Hopkins syndrome |
What are the genetic changes related to Pitt-Hopkins syndrome ? | Mutations in the TCF4 gene cause Pitt-Hopkins syndrome. This gene provides instructions for making a protein that attaches (binds) to other proteins and then binds to specific regions of DNA to help control the activity of many other genes. On the basis of its DNA binding and gene controlling activities, the TCF4 protein is known as a transcription factor. The TCF4 protein plays a role in the maturation of cells to carry out specific functions (cell differentiation) and the self-destruction of cells (apoptosis). TCF4 gene mutations disrupt the protein's ability to bind to DNA and control the activity of certain genes. These disruptions, particularly the inability of the TCF4 protein to control the activity of genes involved in nervous system development and function, contribute to the signs and symptoms of Pitt-Hopkins syndrome. Furthermore, additional proteins interact with the TCF4 protein to carry out specific functions. When the TCF4 protein is nonfunctional, these other proteins are also unable to function normally. It is also likely that the loss of the normal proteins that are attached to the nonfunctional TCF4 proteins contribute to the features of this condition. The loss of one protein in particular, the ASCL1 protein, is thought to be associated with breathing problems in people with Pitt-Hopkins syndrome. | Pitt-Hopkins syndrome |
Is Pitt-Hopkins syndrome inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. | Pitt-Hopkins syndrome |
What are the treatments for Pitt-Hopkins syndrome ? | These resources address the diagnosis or management of Pitt-Hopkins syndrome: - Gene Review: Gene Review: Pitt-Hopkins Syndrome - Genetic Testing Registry: Pitt-Hopkins syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Pitt-Hopkins syndrome |
What is (are) PPM-X syndrome ? | PPM-X syndrome is a condition characterized by psychotic disorders (most commonly bipolar disorder), a pattern of movement abnormalities known as parkinsonism, and mild to severe intellectual disability. Other symptoms include increased muscle tone and exaggerated reflexes. Affected males may have enlarged testes (macro-orchidism). Not all affected individuals have all these symptoms, but most have intellectual disability. Males with this condition are typically more severely affected than females, who usually have only mild intellectual disability. | PPM-X syndrome |
How many people are affected by PPM-X syndrome ? | The prevalence of PPM-X syndrome is unknown. | PPM-X syndrome |
What are the genetic changes related to PPM-X syndrome ? | Mutations in the MECP2 gene cause PPM-X syndrome. The MECP2 gene provides instructions for making a protein called MeCP2 that is critical for normal brain function. Researchers believe that this protein has several functions, including regulating other genes in the brain by switching them off when they are not needed. The MeCP2 protein likely plays a role in maintaining connections (synapses) between nerve cells. The MeCP2 protein may also control the production of different versions of certain proteins in nerve cells. Although mutations in the MECP2 gene disrupt the normal function of nerve cells, it is unclear how these mutations lead to the signs and symptoms of PPM-X syndrome. Some MECP2 gene mutations that cause PPM-X syndrome disrupt attachment (binding) of the MeCP2 protein to DNA, and other mutations alter the 3-dimensional shape of the protein. These mutations lead to the production of a MeCP2 protein that cannot properly interact with DNA or other proteins and so cannot control the expression of genes. It is unclear how MECP2 gene mutations lead to the signs and symptoms of PPM-X syndrome, but misregulation of genes in the brain likely plays a role. | PPM-X syndrome |
Is PPM-X syndrome inherited ? | More than 99 percent of PPM-X syndrome cases occur in people with no history of the disorder in their family. Many of these cases result from new mutations in the MECP2 gene. A few families with more than one affected family member have been described. These cases helped researchers determine that PPM-X syndrome has 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. One copy of the altered gene in each cell is sufficient to cause the condition, although females with one altered copy of the gene are usually less severely affected than males. | PPM-X syndrome |
What are the treatments for PPM-X syndrome ? | These resources address the diagnosis or management of PPM-X syndrome: - Cincinnati Children's Hospital: MECP2-Related Disorders - Gene Review: Gene Review: MECP2-Related Disorders These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | PPM-X syndrome |
What is (are) cardiofaciocutaneous syndrome ? | Cardiofaciocutaneous syndrome is a disorder that affects many parts of the body, particularly the heart (cardio-), facial features (facio-), and the skin and hair (cutaneous). People with this condition also have delayed development and intellectual disability, usually ranging from moderate to severe. Heart defects occur in most people with cardiofaciocutaneous syndrome. The heart problems most commonly associated with this condition include malformations of one of the heart valves that impairs blood flow from the heart to the lungs (pulmonic stenosis), a hole between the two upper chambers of the heart (atrial septal defect), and a form of heart disease that enlarges and weakens the heart muscle (hypertrophic cardiomyopathy). Cardiofaciocutaneous syndrome is also characterized by distinctive facial features. These include a high forehead that narrows at the temples, a short nose, widely spaced eyes (ocular hypertelorism), outside corners of the eyes that point downward (down-slanting palpebral fissures), droopy eyelids (ptosis), a small chin, and low-set ears. Overall, the face is broad and long, and the facial features are sometimes described as "coarse." Skin abnormalities occur in almost everyone with cardiofaciocutaneous syndrome. Many affected people have dry, rough skin; dark-colored moles (nevi); wrinkled palms and soles; and a skin condition called keratosis pilaris, which causes small bumps to form on the arms, legs, and face. People with cardiofaciocutaneous syndrome also tend to have thin, dry, curly hair and sparse or absent eyelashes and eyebrows. Infants with cardiofaciocutaneous syndrome typically have weak muscle tone (hypotonia), feeding difficulties, and a failure to grow and gain weight at the normal rate (failure to thrive). Additional features of this disorder in children and adults can include an unusually large head (macrocephaly), short stature, problems with vision, and seizures. The signs and symptoms of cardiofaciocutaneous syndrome overlap significantly with those of two other genetic conditions, Costello syndrome and Noonan syndrome. The three conditions are distinguished by their genetic cause and specific patterns of signs and symptoms; however, it can be difficult to tell these conditions apart, particularly in infancy. Unlike Costello syndrome, which significantly increases a person's cancer risk, cancer does not appear to be a major feature of cardiofaciocutaneous syndrome. | cardiofaciocutaneous syndrome |
How many people are affected by cardiofaciocutaneous syndrome ? | Cardiofaciocutaneous syndrome is a very rare condition whose incidence is unknown. Researchers estimate that 200 to 300 people worldwide have this condition. | cardiofaciocutaneous syndrome |
What are the genetic changes related to cardiofaciocutaneous syndrome ? | Cardiofaciocutaneous syndrome can be caused by mutations in several genes. Mutations in the BRAF gene are most common, accounting for 75 to 80 percent of all cases. Another 10 to 15 percent of cases result from mutations in one of two similar genes, MAP2K1 and MAP2K2. Fewer than 5 percent of cases are caused by mutations in the KRAS gene. The BRAF, MAP2K1, MAP2K2, and KRAS genes provide instructions for making proteins that work together to transmit chemical signals from outside the cell to the cell's nucleus. This chemical signaling pathway, known as the RAS/MAPK pathway, is essential for normal development before birth. It helps control the growth and division (proliferation) of cells, the process by which cells mature to carry out specific functions (differentiation), cell movement, and the self-destruction of cells (apoptosis). Mutations in any of these genes can result in the characteristic features of cardiofaciocutaneous syndrome. The protein made from the mutated gene is overactive, which alters tightly regulated chemical signaling during development. The altered signaling interferes with the development of many organs and tissues, leading to the signs and symptoms of cardiofaciocutaneous syndrome. Some people with the signs and symptoms of cardiofaciocutaneous syndrome do not have an identified mutation in the BRAF, MAP2K1, MAP2K2, or KRAS gene. In these cases, affected individuals may actually have Costello syndrome or Noonan syndrome, which are also caused by mutations in genes involved in RAS/MAPK signaling. The proteins produced from these genes are all part of the same chemical signaling pathway, which helps explain why mutations in different genes can cause conditions with such similar signs and symptoms. The group of related conditions that includes cardiofaciocutaneous syndrome, Costello syndrome, and Noonan syndrome is often called the RASopathies. | cardiofaciocutaneous syndrome |
Is cardiofaciocutaneous syndrome inherited ? | Cardiofaciocutaneous syndrome is considered to be an autosomal dominant condition, which means one copy of an altered gene in each cell is sufficient to cause the disorder. Cardiofaciocutaneous syndrome usually results from new gene mutations and occurs in people with no history of the disorder in their family. In a few reported cases, an affected person has inherited the condition from an affected parent. | cardiofaciocutaneous syndrome |
What are the treatments for cardiofaciocutaneous syndrome ? | These resources address the diagnosis or management of cardiofaciocutaneous syndrome: - Gene Review: Gene Review: Cardiofaciocutaneous Syndrome - Genetic Testing Registry: Cardiofaciocutaneous syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | cardiofaciocutaneous syndrome |
What is (are) Ghosal hematodiaphyseal dysplasia ? | Ghosal hematodiaphyseal dysplasia is a rare inherited condition characterized by abnormally thick bones and a shortage of red blood cells (anemia). Signs and symptoms of the condition become apparent in early childhood. In affected individuals, the long bones in the arms and legs are unusually dense and wide. The bone changes specifically affect the shafts of the long bones, called diaphyses, and areas near the ends of the bones called metaphyses. The bone abnormalities can lead to bowing of the legs and difficulty walking. Ghosal hematodiaphyseal dysplasia also causes scarring (fibrosis) of the bone marrow, which is the spongy tissue inside long bones where blood cells are formed. The abnormal bone marrow cannot produce enough red blood cells, which leads to anemia.Signs and symptoms of anemia that have been reported in people with Ghosal hematodiaphyseal dysplasia include extremely pale skin (pallor) and excessive tiredness (fatigue). | Ghosal hematodiaphyseal dysplasia |
How many people are affected by Ghosal hematodiaphyseal dysplasia ? | Ghosal hematodiaphyseal dysplasia is a rare disorder; only a few cases have been reported in the medical literature. Most affected individuals have been from the Middle East and India. | Ghosal hematodiaphyseal dysplasia |
What are the genetic changes related to Ghosal hematodiaphyseal dysplasia ? | Ghosal hematodiaphyseal dysplasia results from mutations in the TBXAS1 gene. This gene provides instructions for making an enzyme called thromboxane A synthase 1, which acts as part of a chemical signaling pathway involved in normal blood clotting (hemostasis). Based on its role in Ghosal hematodiaphyseal dysplasia, researchers suspect that thromboxane A synthase 1 may also be important for bone remodeling, which is a normal process in which old bone is removed and new bone is created to replace it, and for the production of red blood cells in bone marrow. Mutations in the TBXAS1 gene severely reduce the activity of thromboxane A synthase 1. Studies suggest that a lack of this enzyme's activity may lead to abnormal bone remodeling and fibrosis of the bone marrow. However, the mechanism by which a shortage of thromboxane A synthase 1 activity leads to the particular abnormalities characteristic of Ghosal hematodiaphyseal dysplasia is unclear. | Ghosal hematodiaphyseal dysplasia |
Is Ghosal hematodiaphyseal dysplasia inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | Ghosal hematodiaphyseal dysplasia |
What are the treatments for Ghosal hematodiaphyseal dysplasia ? | These resources address the diagnosis or management of Ghosal hematodiaphyseal dysplasia: - Genetic Testing Registry: Ghosal syndrome - National Heart, Lung, and Blood Institute: How is Anemia Diagnosed? - National Heart, Lung, and Blood Institute: How is Anemia Treated? These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Ghosal hematodiaphyseal dysplasia |
What is (are) Bart-Pumphrey syndrome ? | Bart-Pumphrey syndrome is characterized by nail and skin abnormalities and hearing loss. People with Bart-Pumphrey syndrome typically have a white discoloration of the nails (leukonychia); the nails may also be thick and crumbly. Affected individuals often have wart-like (verrucous) skin growths called knuckle pads on the knuckles of the fingers and toes. They may also have thickening of the skin on the palms of the hands and soles of the feet (palmoplantar keratoderma). The skin abnormalities generally become noticeable during childhood. The hearing loss associated with Bart-Pumphrey syndrome ranges from moderate to profound and is typically present from birth (congenital). The signs and symptoms of this disorder may vary even within the same family; while almost all affected individuals have hearing loss, they may have different combinations of the other associated features. | Bart-Pumphrey syndrome |
How many people are affected by Bart-Pumphrey syndrome ? | Bart-Pumphrey syndrome is a rare disorder; its exact prevalence is unknown. Only a few affected families and individual cases have been identified. | Bart-Pumphrey syndrome |
What are the genetic changes related to Bart-Pumphrey syndrome ? | Bart-Pumphrey syndrome is caused by mutations in the GJB2 gene. This gene provides instructions for making a protein called gap junction beta 2, more commonly known as connexin 26. Connexin 26 is a member of the connexin protein family. Connexin proteins form channels called gap junctions that permit the transport of nutrients, charged atoms (ions), and signaling molecules between neighboring cells that are in contact with each other. Gap junctions made with connexin 26 transport potassium ions and certain small molecules. Connexin 26 is found in cells throughout the body, including the inner ear and the skin. In the inner ear, channels made from connexin 26 are found in a snail-shaped structure called the cochlea. These channels may help to maintain the proper level of potassium ions required for the conversion of sound waves to electrical nerve impulses. This conversion is essential for normal hearing. In addition, connexin 26 may be involved in the maturation of certain cells in the cochlea. Connexin 26 also plays a role in the growth, maturation, and stability of the outermost layer of skin (the epidermis). The GJB2 gene mutations that cause Bart-Pumphrey syndrome change single protein building blocks (amino acids) in the connexin 26 protein. The altered protein probably disrupts the function of normal connexin 26 in cells, and may interfere with the function of other connexin proteins. This disruption could affect skin growth and also impair hearing by disturbing the conversion of sound waves to nerve impulses. | Bart-Pumphrey syndrome |
Is Bart-Pumphrey syndrome inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family. | Bart-Pumphrey syndrome |
What are the treatments for Bart-Pumphrey syndrome ? | These resources address the diagnosis or management of Bart-Pumphrey syndrome: - Foundation for Ichthyosis and Related Skin Types: Palmoplantar Keratoderma - Genetic Testing Registry: Knuckle pads, deafness AND leukonychia syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Bart-Pumphrey syndrome |
What is (are) coloboma ? | Coloboma is an eye abnormality that occurs before birth. Colobomas are missing pieces of tissue in structures that form the eye. They may appear as notches or gaps in one of several parts of the eye, including the colored part of the eye called the iris; the retina, which is the specialized light-sensitive tissue that lines the back of the eye; the blood vessel layer under the retina called the choroid; or the optic nerves, which carry information from the eyes to the brain. Colobomas may be present in one or both eyes and, depending on their size and location, can affect a person's vision. Colobomas affecting the iris, which result in a "keyhole" appearance of the pupil, generally do not lead to vision loss. Colobomas involving the retina result in vision loss in specific parts of the visual field, generally the upper part. Large retinal colobomas or those affecting the optic nerve can cause low vision, which means vision loss that cannot be completely corrected with glasses or contact lenses. Some people with coloboma also have a condition called microphthalmia. In this condition, one or both eyeballs are abnormally small. In some affected individuals, the eyeball may appear to be completely missing; however, even in these cases some remaining eye tissue is generally present. Such severe microphthalmia should be distinguished from another condition called anophthalmia, in which no eyeball forms at all. However, the terms anophthalmia and severe microphthalmia are often used interchangeably. Microphthalmia may or may not result in significant vision loss. People with coloboma may also have other eye abnormalities, including clouding of the lens of the eye (cataract), increased pressure inside the eye (glaucoma) that can damage the optic nerve, vision problems such as nearsightedness (myopia), involuntary back-and-forth eye movements (nystagmus), or separation of the retina from the back of the eye (retinal detachment). Some individuals have coloboma as part of a syndrome that affects other organs and tissues in the body. These forms of the condition are described as syndromic. When coloboma occurs by itself, it is described as nonsyndromic or isolated. Colobomas involving the eyeball should be distinguished from gaps that occur in the eyelids. While these eyelid gaps are also called colobomas, they arise from abnormalities in different structures during early development. | coloboma |
How many people are affected by coloboma ? | Coloboma occurs in approximately 1 in 10,000 people. Because coloboma does not always affect vision or the outward appearance of the eye, some people with this condition are likely undiagnosed. | coloboma |
What are the genetic changes related to coloboma ? | Coloboma arises from abnormal development of the eye. During the second month of development before birth, a seam called the optic fissure (also known as the choroidal fissure or embryonic fissure) closes to form the structures of the eye. When the optic fissure does not close completely, the result is a coloboma. The location of the coloboma depends on the part of the optic fissure that failed to close. Coloboma may be caused by changes in many genes involved in the early development of the eye, most of which have not been identified. The condition may also result from a chromosomal abnormality affecting one or more genes. Most genetic changes associated with coloboma have been identified only in very small numbers of affected individuals. The risk of coloboma may also be increased by environmental factors that affect early development, such as exposure to alcohol during pregnancy. In these cases, affected individuals usually have other health problems in addition to coloboma. | coloboma |
Is coloboma inherited ? | Most often, isolated coloboma is not inherited, and there is only one affected individual in a family. However, the affected individual is still at risk of passing the coloboma on to his or her own children. In cases when it is passed down in families, coloboma can have different inheritance patterns. Isolated coloboma is sometimes inherited in an autosomal dominant pattern, which means one copy of an altered gene in each cell is sufficient to cause the disorder. Isolated coloboma can also be inherited in an autosomal recessive pattern, 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 a mutated gene, but they typically do not show signs and symptoms of the condition. Less commonly, isolated coloboma may have X-linked dominant or X-linked recessive patterns of inheritance. X-linked means that a gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. X-linked dominant means that in females (who have two X chromosomes), a mutation in one of the two copies of a gene in each cell is sufficient to cause the disorder. In males (who have only one X chromosome), a mutation in the only copy of a gene in each cell causes the disorder. In most cases, males experience more severe symptoms of the disorder than females. X-linked recessive means that in females, a mutation would have to occur in both copies of a gene to cause the disorder. In males, one altered copy of a gene in each cell is sufficient to cause the condition. Because it is unlikely that females will have two altered copies of a particular gene, males are affected by X-linked recessive disorders much more frequently than females. When coloboma occurs as a feature of a genetic syndrome or chromosomal abnormality, it may cluster in families according to the inheritance pattern for that condition, which may be autosomal dominant, autosomal recessive, or X-linked. | coloboma |
What are the treatments for coloboma ? | These resources address the diagnosis or management of coloboma: - Genetic Testing Registry: Congenital ocular coloboma - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 1 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 2 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 3 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 4 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 5 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 6 - National Eye Institute: Facts About Uveal Coloboma 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 | coloboma |
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