bowang0911/MedQuAD huggingface dataset:
Waardenburg syndrome is a group of genetic conditions that can cause hearing loss and changes in coloring (pigmentation) of the hair, skin, and eyes. Although most people with Waardenburg syndrome have normal hearing, moderate to profound hearing loss can occur in one or both ears. The hearing loss is present from birth (congenital). People with this condition often have very pale blue eyes or different colored eyes, such as one blue eye and one brown eye. Sometimes one eye has segments of two different colors. Distinctive hair coloring (such as a patch of white hair or hair that prematurely turns gray) is another common sign of the condition. The features of Waardenburg syndrome vary among affected individuals, even among people in the same family.  The four known types of Waardenburg syndrome are distinguished by their physical characteristics and sometimes by their genetic cause. Types I and II have very similar features, although people with type I almost always have eyes that appear widely spaced and people with type II do not. In addition, hearing loss occurs more often in people with type II than in those with type I. Type III (sometimes called Klein-Waardenburg syndrome) includes abnormalities of the upper limbs in addition to hearing loss and changes in pigmentation. Type IV (also known as Waardenburg-Shah syndrome) has signs and symptoms of both Waardenburg syndrome and Hirschsprung disease, an intestinal disorder that causes severe constipation or blockage of the intestine.
Mutations in the EDN3, EDNRB, MITF, PAX3, SNAI2, and SOX10 genes can cause Waardenburg syndrome. These genes are involved in the formation and development of several types of cells, including pigment-producing cells called melanocytes. Melanocytes make a pigment called melanin, which contributes to skin, hair, and eye color and plays an essential role in the normal function of the inner ear. Mutations in any of these genes disrupt the normal development of melanocytes, leading to abnormal pigmentation of the skin, hair, and eyes and problems with hearing.  Types I and III Waardenburg syndrome are caused by mutations in the PAX3 gene. Mutations in the MITF and SNAI2 genes are responsible for type II Waardenburg syndrome.  Mutations in the SOX10, EDN3, or EDNRB genes cause type IV Waardenburg syndrome. In addition to melanocyte development, these genes are important for the development of nerve cells in the large intestine. Mutations in any of these genes result in hearing loss, changes in pigmentation, and intestinal problems related to Hirschsprung disease.
Waardenburg syndrome 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. In most cases, an affected person has one parent with the condition. A small percentage of cases result from new mutations in the gene; these cases occur in people with no history of the disorder in their family.  Some cases of type II and type IV Waardenburg syndrome appear to have an autosomal recessive pattern of inheritance, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition.
These resources address the diagnosis or management of Waardenburg syndrome:  - Gene Review: Gene Review: Waardenburg Syndrome Type I  - Genetic Testing Registry: Klein-Waardenberg's syndrome  - Genetic Testing Registry: Waardenburg syndrome type 1  - Genetic Testing Registry: Waardenburg syndrome type 2A  - Genetic Testing Registry: Waardenburg syndrome type 2B  - Genetic Testing Registry: Waardenburg syndrome type 2C  - Genetic Testing Registry: Waardenburg syndrome type 2D  - Genetic Testing Registry: Waardenburg syndrome type 4A  - MedlinePlus Encyclopedia: Waardenburg 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
Glutaric acidemia type I is an inherited disorder in which the body is unable to process certain proteins properly. People with this disorder have inadequate levels of an enzyme that helps break down the amino acids lysine, hydroxylysine, and tryptophan, which are building blocks of protein. Excessive levels of these amino acids and their intermediate breakdown products can accumulate and cause damage to the brain, particularly the basal ganglia, which are regions that help control movement. Intellectual disability may also occur.  The severity of glutaric acidemia type I varies widely; some individuals are only mildly affected, while others have severe problems. In most cases, signs and symptoms first occur in infancy or early childhood, but in a small number of affected individuals, the disorder first becomes apparent in adolescence or adulthood.  Some babies with glutaric acidemia type I are born with unusually large heads (macrocephaly). Affected individuals may have difficulty moving and may experience spasms, jerking, rigidity, or decreased muscle tone. Some individuals with glutaric acidemia have developed bleeding in the brain or eyes that could be mistaken for the effects of child abuse. Strict dietary control may help limit progression of the neurological damage. Stress caused by infection, fever or other demands on the body may lead to worsening of the signs and symptoms, with only partial recovery.
Mutations in the GCDH gene cause glutaric acidemia type I.  The GCDH gene provides instructions for making the enzyme glutaryl-CoA dehydrogenase. This enzyme is involved in processing the amino acids lysine, hydroxylysine, and tryptophan.  Mutations in the GCDH gene prevent production of the enzyme or result in the production of a defective enzyme that cannot function. This enzyme deficiency allows lysine, hydroxylysine and tryptophan and their intermediate breakdown products to build up to abnormal levels, especially at times when the body is under stress.  The intermediate breakdown products resulting from incomplete processing of lysine, hydroxylysine, and tryptophan can damage the brain, particularly the basal ganglia, causing the signs and symptoms of glutaric acidemia type I.
Pseudohypoaldosteronism type 2 (PHA2) is caused by problems that affect regulation of the amount of sodium and potassium in the body. Sodium and potassium are important in the control of blood pressure, and their regulation occurs primarily in the kidneys.  People with PHA2 have high blood pressure (hypertension) and high levels of potassium in their blood (hyperkalemia) despite having normal kidney function. The age of onset of PHA2 is variable and difficult to pinpoint; some affected individuals are diagnosed in infancy or childhood, and others are diagnosed in adulthood. Hyperkalemia usually occurs first, and hypertension develops later in life. Affected individuals also have high levels of chloride (hyperchloremia) and acid (metabolic acidosis) in their blood (together, referred to as hyperchloremic metabolic acidosis). People with hyperkalemia, hyperchloremia, and metabolic acidosis can have nonspecific symptoms like nausea, vomiting, extreme tiredness (fatigue), and muscle weakness. People with PHA2 may also have high levels of calcium in their urine (hypercalciuria).
PHA2 can be caused by mutations in the WNK1, WNK4, CUL3, or KLHL3 gene. These genes play a role in the regulation of blood pressure.  The proteins produced from the WNK1 and WNK4 genes help control the amount of sodium and potassium in the body by regulating channels in the cell membrane that control the transport of sodium or potassium into and out of cells. This process primarily occurs in the kidneys. Mutations in either of these genes disrupt control of these channels, leading to abnormal levels of sodium and potassium in the body. As a result, affected individuals develop hypertension and hyperkalemia.  The proteins produced from the CUL3 gene (called cullin-3) and the KLHL3 gene help control the amount of WNK1 and WNK4 protein available. Cullin-3 and KLHL3 are two pieces of a complex, called an E3 ubiquitin ligase, that tags certain other proteins with molecules called ubiquitin. This molecule acts as a signal for the tagged protein to be broken down when it is no longer needed. E3 ubiquitin ligases containing cullin-3 and KLHL3 are able to tag the WNK1 and WNK4 proteins with ubiquitin, leading to their breakdown. Mutations in either the CUL3 or KLHL3 gene impair breakdown of the WNK4 protein. (The effect of these mutations on the WNK1 protein is unclear.) An excess of WNK4 likely disrupts control of sodium and potassium levels, resulting in hypertension and hyperkalemia.
This condition 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. In most cases caused by mutations in the WNK1, WNK4, or KLHL3 gene, an affected person inherits the mutation from one affected parent. While some cases caused by CUL3 gene mutations can be inherited from an affected parent, many result from new mutations in the gene and occur in people with no history of the disorder in their family.  Some cases caused by mutations in the KLHL3 gene are 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.
These resources address the diagnosis or management of pseudohypoaldosteronism type 2:  - Gene Review: Gene Review: Pseudohypoaldosteronism Type II  - Genetic Testing Registry: Pseudohypoaldosteronism, type 2   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
Nonsyndromic hearing loss is a partial or total loss of hearing that is not associated with other signs and symptoms. In contrast, syndromic hearing loss occurs with signs and symptoms affecting other parts of the body.  Nonsyndromic hearing loss can be classified in several different ways. One common way is by the condition's pattern of inheritance: autosomal dominant (DFNA), autosomal recessive (DFNB), X-linked (DFNX), or mitochondrial (which does not have a special designation). Each of these types of hearing loss includes multiple subtypes. DFNA, DFNB, and DFNX subtypes are numbered in the order in which they were first described. For example, DFNA1 was the first type of autosomal dominant nonsyndromic hearing loss to be identified. The various inheritance patterns of nonsyndromic hearing loss are described in more detail below.  The characteristics of nonsyndromic hearing loss vary among the different types. Hearing loss can affect one ear (unilateral) or both ears (bilateral). Degrees of hearing loss range from mild (difficulty understanding soft speech) to profound (inability to hear even very loud noises). The term "deafness" is often used to describe severe-to-profound hearing loss. Hearing loss can be stable, or it may be progressive, becoming more severe as a person gets older. Particular types of nonsyndromic hearing loss show distinctive patterns of hearing loss. For example, the loss may be more pronounced at high, middle, or low tones.  Most forms of nonsyndromic hearing loss are described as sensorineural, which means they are associated with a permanent loss of hearing caused by damage to structures in the inner ear. The inner ear processes sound and sends the information to the brain in the form of electrical nerve impulses. Less commonly, nonsyndromic hearing loss is described as conductive, meaning it results from changes in the middle ear. The middle ear contains three tiny bones that help transfer sound from the eardrum to the inner ear. Some forms of nonsyndromic hearing loss, particularly a type called DFNX2, involve changes in both the inner ear and the middle ear. This combination is called mixed hearing loss.  Depending on the type, nonsyndromic hearing loss can become apparent at any time from infancy to old age. Hearing loss that is present before a child learns to speak is classified as prelingual or congenital. Hearing loss that occurs after the development of speech is classified as postlingual.
As discussed above, nonsyndromic hearing loss has different patterns of inheritance. Between 75 and 80 percent of cases are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Usually, each parent of an individual with autosomal recessive hearing loss carries one copy of the mutated gene but does not have hearing loss.  Another 20 to 25 percent of nonsyndromic hearing loss has an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the condition. Most people with autosomal dominant hearing loss inherit an altered copy of the gene from a parent who also has hearing loss.  Between 1 and 2 percent of cases have an X-linked pattern of inheritance. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. Males with X-linked nonsyndromic hearing loss tend to develop more severe hearing loss earlier in life than females who inherit a copy of the same gene mutation. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.  Mitochondrial forms of the condition, which result from changes to mtDNA, account for less than 1 percent of all nonsyndromic hearing loss in the United States. These cases are inherited in a mitochondrial pattern, which is also known as maternal inheritance. This pattern of inheritance applies to genes contained in mtDNA. Because egg cells, but not sperm cells, contribute mitochondria to the developing embryo, children can only inherit disorders resulting from mtDNA mutations from their mother. These disorders can appear in every generation of a family and can affect both males and females, but fathers do not pass traits associated with changes in mtDNA to their children.  In some cases, hearing loss occurs in people with no history of the condition in their family. These cases are described as sporadic, and the cause of the hearing loss is often unknown. When hearing loss results from environmental factors, it is not inherited.
These resources address the diagnosis or management of nonsyndromic hearing loss:  - Baby's First Test: Hearing Loss  - Gene Review: Gene Review: Deafness and Hereditary Hearing Loss Overview  - Genetic Testing Registry: Deafness, X-linked  - Genetic Testing Registry: Hereditary hearing loss and deafness  - Genetic Testing Registry: Non-syndromic genetic deafness  - MedlinePlus Encyclopedia: Age-related hearing loss  - MedlinePlus Encyclopedia: Audiology  - MedlinePlus Encyclopedia: Hearing loss  - MedlinePlus Encyclopedia: Hearing or speech impairment - resources   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
Cap myopathy is a disorder that primarily affects skeletal muscles, which are muscles that the body uses for movement. People with cap myopathy have muscle weakness (myopathy) and poor muscle tone (hypotonia) throughout the body, but they are most severely affected in the muscles of the face, neck, and limbs. The muscle weakness, which begins at birth or during childhood, can worsen over time.  Affected individuals may have feeding and swallowing difficulties in infancy. They typically have delayed development of motor skills such as sitting, crawling, standing, and walking. They may fall frequently, tire easily, and have difficulty running, climbing stairs, or jumping. In some cases, the muscles used for breathing are affected, and life-threatening breathing difficulties can occur.  People with cap myopathy may have a high arch in the roof of the mouth (high-arched palate), severely drooping eyelids (ptosis), and a long face. Some affected individuals develop an abnormally curved lower back (lordosis) or a spine that curves to the side (scoliosis).  The name cap myopathy comes from characteristic abnormal cap-like structures that can be seen in muscle cells when muscle tissue is viewed under a microscope. The severity of cap myopathy is related to the percentage of muscle cells that have these caps. Individuals in whom 70 to 75 percent of muscle cells have caps typically have severe breathing problems and may not survive childhood, while those in whom 10 to 30 percent of muscle cells have caps have milder symptoms and can live into adulthood.
Mutations in the ACTA1, TPM2, or TPM3 genes can cause cap myopathy. These genes provide instructions for producing proteins that play important roles in skeletal muscles.  The ACTA1 gene provides instructions for making a protein called skeletal alpha ()-actin, which is part of the actin protein family. Actin proteins are important for cell movement and the tensing of muscle fibers (muscle contraction). Thin filaments made up of actin molecules and thick filaments made up of another protein called myosin are the primary components of muscle fibers and are important for muscle contraction. Attachment (binding) and release of the overlapping thick and thin filaments allows them to move relative to each other so that the muscles can contract. The mutation in the ACTA1 gene that causes cap myopathy results in an abnormal protein that may interfere with the proper assembly of thin filaments. The cap structures in muscle cells characteristic of this disorder are composed of disorganized thin filaments.  The TPM2 and TPM3 genes provide instructions for making proteins that are members of the tropomyosin protein family. Tropomyosin proteins regulate muscle contraction by attaching to actin and controlling its binding to myosin. The specific effects of TPM2 and TPM3 gene mutations are unclear, but researchers suggest they may interfere with normal actin-myosin binding between the thin and thick filaments, impairing muscle contraction and resulting in the muscle weakness that occurs in cap myopathy.
Donnai-Barrow syndrome is an inherited disorder that affects many parts of the body. This disorder is characterized by unusual facial features, including prominent, wide-set eyes with outer corners that point downward; a short bulbous nose with a flat nasal bridge; ears that are rotated backward; and a widow's peak hairline.  Individuals with Donnai-Barrow syndrome have severe hearing loss caused by abnormalities of the inner ear (sensorineural hearing loss). In addition, they often experience vision problems, including extreme nearsightedness (high myopia), detachment or deterioration of the light-sensitive tissue in the back of the eye (the retina), and progressive vision loss. Some have a gap or split in the colored part of the eye (iris coloboma).  In almost all people with Donnai-Barrow syndrome, the tissue connecting the left and right halves of the brain (corpus callosum) is underdeveloped or absent. Affected individuals may also have other structural abnormalities of the brain. They generally have mild to moderate intellectual disability and developmental delay.  People with Donnai-Barrow syndrome may also have a hole in the muscle that separates the abdomen from the chest cavity (the diaphragm), which is called a congenital diaphragmatic hernia. This potentially serious birth defect allows the stomach and intestines to move into the chest and possibly crowd the developing heart and lungs. An opening in the wall of the abdomen (an omphalocele) that allows the abdominal organs to protrude through the navel may also occur in affected individuals. Occasionally people with Donnai-Barrow syndrome have abnormalities of the intestine, heart, or other organs.
Mutations in the LRP2 gene cause Donnai-Barrow syndrome. The LRP2 gene provides instructions for making a protein called megalin, which functions as a receptor. Receptor proteins have specific sites into which certain other proteins, called ligands, fit like keys into locks. Together, ligands and their receptors trigger signals that affect cell development and function. Megalin has many ligands involved in various body processes, including the absorption of vitamins A and D, immune functioning, stress response, and the transport of fats in the bloodstream.  Megalin is embedded in the membrane of cells that line the surfaces and cavities of the body (epithelial cells). The receptor helps move its ligands from the cell surface into the cell (endocytosis). It is active in the development and function of many parts of the body, including the brain and spinal cord (central nervous system), eyes, ears, lungs, intestine, reproductive system, and the small tubes in the kidneys where urine is formed (renal tubules).  LRP2 gene mutations that cause Donnai-Barrow syndrome are believed to result in the absence of functional megalin protein. The lack of functional megalin in the renal tubules causes megalin's various ligands to be excreted in the urine rather than being absorbed back into the bloodstream. The features of Donnai-Barrow syndrome are probably caused by the inability of megalin to help absorb these ligands, disruption of biochemical signaling pathways, or other effects of the nonfunctional megalin protein. However, it is unclear how these abnormalities result in the specific signs and symptoms of the disorder.  A condition previously classified as a separate disorder called facio-oculo-acoustico-renal (FOAR) syndrome has also been found to be caused by LRP2 mutations. FOAR syndrome is now considered to be the same disorder as Donnai-Barrow syndrome.
This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. In almost all cases, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene but typically do not show signs and symptoms of the condition.  One individual with Donnai-Barrow syndrome was found to have inherited both copies of the mutated gene from his father as a result of a genetic change called uniparental disomy (UPD). UPD occurs when a person receives two copies of a chromosome, or part of a chromosome, from one parent and no copies from the other parent. UPD can occur as a random event during the formation of egg or sperm cells or may happen in early fetal development.
These resources address the diagnosis or management of Donnai-Barrow syndrome:  - Gene Review: Gene Review: Donnai-Barrow Syndrome  - Genetic Testing Registry: Donnai Barrow syndrome  - MedlinePlus Encyclopedia: Diaphragmatic Hernia  - MedlinePlus Encyclopedia: Hearing Loss - Infants  - MedlinePlus Encyclopedia: Omphalocele  - Nemours Foundation: Hearing Evaluation in Children   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