bowang0911/MedQuAD huggingface dataset:
Vitelliform macular dystrophy is a genetic eye disorder that can cause progressive vision loss. This disorder affects the retina, the specialized light-sensitive tissue that lines the back of the eye. Specifically, vitelliform macular dystrophy disrupts cells in a small area near the center of the retina called the macula. The macula is responsible for sharp central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces.  Vitelliform macular dystrophy causes a fatty yellow pigment (lipofuscin) to build up in cells underlying the macula. Over time, the abnormal accumulation of this substance can damage cells that are critical for clear central vision. As a result, people with this disorder often lose their central vision, and their eyesight may become blurry or distorted. Vitelliform macular dystrophy typically does not affect side (peripheral) vision or the ability to see at night.  Researchers have described two forms of vitelliform macular dystrophy with similar features. The early-onset form (known as Best disease) usually appears in childhood; the onset of symptoms and the severity of vision loss vary widely. The adult-onset form begins later, usually in mid-adulthood, and tends to cause vision loss that worsens slowly over time. The two forms of vitelliform macular dystrophy each have characteristic changes in the macula that can be detected during an eye examination.
Mutations in the BEST1 and PRPH2 genes cause vitelliform macular dystrophy. BEST1 mutations are responsible for Best disease and for some cases of the adult-onset form of vitelliform macular dystrophy. Changes in the PRPH2 gene can also cause the adult-onset form of vitelliform macular dystrophy; however, less than a quarter of all people with this form of the condition have mutations in the BEST1 or PRPH2 gene. In most cases, the cause of the adult-onset form is unknown.  The BEST1 gene provides instructions for making a protein called bestrophin. This protein acts as a channel that controls the movement of charged chlorine atoms (chloride ions) into or out of cells in the retina. Mutations in the BEST1 gene probably lead to the production of an abnormally shaped channel that cannot properly regulate the flow of chloride. Researchers have not determined how these malfunctioning channels are related to the buildup of lipofuscin in the macula and progressive vision loss.  The PRPH2 gene provides instructions for making a protein called peripherin 2. This protein is essential for the normal function of light-sensing (photoreceptor) cells in the retina. Mutations in the PRPH2 gene cause vision loss by disrupting structures in these cells that contain light-sensing pigments. It is unclear why PRPH2 mutations affect only central vision in people with adult-onset vitelliform macular dystrophy.
Best disease 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.  The inheritance pattern of adult-onset vitelliform macular dystrophy is uncertain. Some studies have suggested that this disorder may be inherited in an autosomal dominant pattern. It is difficult to be sure, however, because many affected people have no history of the disorder in their family, and only a small number of affected families have been reported.
These resources address the diagnosis or management of vitelliform macular dystrophy:  - Gene Review: Gene Review: Best Vitelliform Macular Dystrophy  - Genetic Testing Registry: Macular dystrophy, vitelliform, adult-onset  - Genetic Testing Registry: Vitelliform dystrophy  - MedlinePlus Encyclopedia: Macula (image)   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
Methylmalonic acidemia with homocystinuria is an inherited disorder in which the body is unable to properly process protein building blocks (amino acids), certain fats (lipids), and a waxy fat-like substance called cholesterol. Individuals with this disorder have a combination of features from two separate conditions, methylmalonic acidemia and homocystinuria. The signs and symptoms of the combined condition, methylmalonic acidemia with homocystinuria, usually develop in infancy, although they can begin at any age.  When the condition begins early in life, affected individuals typically have an inability to grow and gain weight at the expected rate (failure to thrive), which is sometimes recognized before birth (intrauterine growth retardation). These infants can also have difficulty feeding and an abnormally pale appearance (pallor). Neurological problems are also common in methylmalonic acidemia with homocystinuria, including weak muscle tone (hypotonia) and seizures. Most infants and children with this condition have an unusually small head size (microcephaly), delayed development, and intellectual disability. Less common features of the condition include eye problems and a blood disorder called megaloblastic anemia. Megaloblastic anemia occurs when a person has a low number of red blood cells (anemia), and the remaining red blood cells are larger than normal (megaloblastic). The signs and symptoms of methylmalonic acidemia with homocystinuria worsen over time, and the condition can be life-threatening if not treated.  When methylmalonic acidemia with homocystinuria begins in adolescence or adulthood, the signs and symptoms usually include psychiatric changes and cognitive problems. Affected individuals can exhibit changes in their behavior and personality; they may become less social and may experience hallucinations, delirium, and psychosis. In addition, these individuals can begin to lose previously acquired mental and movement abilities, resulting in a decline in school or work performance, difficulty controlling movements, memory problems, speech difficulties, a decline in intellectual function (dementia), or an extreme lack of energy (lethargy). Some people with methylmalonic acidemia with homocystinuria whose signs and symptoms begin later in life develop a condition called subacute combined degeneration of the spinal cord, which leads to numbness and weakness in the lower limbs, difficulty walking, and frequent falls.
The most common form of the condition, called methylmalonic acidemia with homocystinuria, cblC type, is estimated to affect 1 in 200,000 newborns worldwide. Studies indicate that this form of the condition may be even more common in particular populations. These studies estimate the condition occurs in 1 in 100,000 people in New York and 1 in 60,000 people in California. Other types of methylmalonic acidemia with homocystinuria are much less common. Fewer than 20 cases of each of the other types have been reported in the medical literature.
Methylmalonic acidemia with homocystinuria can be caused by mutations in one of several genes: MMACHC, MMADHC, LMBRD1, ABCD4, or HCFC1. Mutations in these genes account for the different types of the disorder, which are known as complementation groups: cblC, cblD, cblF, cblJ, and cblX, respectively.  Each of the above-mentioned genes is involved in the processing of vitamin B12, also known as cobalamin or Cbl. Processing of the vitamin converts it to one of two molecules, adenosylcobalamin (AdoCbl) or methylcobalamin (MeCbl). AdoCbl is required for the normal function of an enzyme that helps break down certain amino acids, lipids, and cholesterol. AdoCbl is called a cofactor because it helps the enzyme carry out its function. MeCbl is also a cofactor, but for another enzyme that converts the amino acid homocysteine to another amino acid, methionine. The body uses methionine to make proteins and other important compounds.  Mutations in the MMACHC, MMADHC, LMBRD1, ABCD4, or HCFC1 gene affect early steps of vitamin B12 processing, resulting in a shortage of both AdoCbl and MeCbl. Without AdoCbl, proteins and lipids are not broken down properly. This defect allows potentially toxic compounds to build up in the body's organs and tissues, causing methylmalonic acidemia. Without MeCbl, homocysteine is not converted to methionine. As a result, homocysteine builds up in the bloodstream and methionine is depleted. Some of the excess homocysteine is excreted in urine (homocystinuria). Researchers have not determined how altered levels of homocysteine and methionine lead to the health problems associated with homocystinuria.  Mutations in other genes involved in vitamin B12 processing can cause related conditions. Those mutations that impair only AdoCbl production lead to methylmalonic acidemia, and those that impair only MeCbl production cause homocystinuria.
Methylmalonic acidemia with homocystinuria is usually inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.  When caused by mutations in the HCFC1 gene, the condition is inherited in an X-linked recessive pattern. The HCFC1 gene is located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
These resources address the diagnosis or management of methylmalonic acidemia with homocystinuria:  - Baby's First Test: Methylmalonic Acidemia with Homocystinuria  - Gene Review: Gene Review: Disorders of Intracellular Cobalamin Metabolism  - Genetic Testing Registry: METHYLMALONIC ACIDURIA AND HOMOCYSTINURIA, cblF TYPE  - Genetic Testing Registry: METHYLMALONIC ACIDURIA AND HOMOCYSTINURIA, cblJ TYPE  - Genetic Testing Registry: Methylmalonic acidemia with homocystinuria  - Genetic Testing Registry: Methylmalonic acidemia with homocystinuria cblD   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
2q37 deletion syndrome is a condition that can affect many parts of the body. This condition is characterized by weak muscle tone (hypotonia) in infancy, mild to severe intellectual disability and developmental delay, behavioral problems, characteristic facial features, and other physical abnormalities.  Most babies with 2q37 deletion syndrome are born with hypotonia, which usually improves with age. About 25 percent of people with this condition have autism, a developmental condition that affects communication and social interaction.  The characteristic facial features associated with 2q37 deletion syndrome include a prominent forehead, highly arched eyebrows, deep-set eyes, a flat nasal bridge, a thin upper lip, and minor ear abnormalities. Other features of this condition can include short stature, obesity, unusually short fingers and toes (brachymetaphalangy), sparse hair, heart defects, seizures, and an inflammatory skin disorder called eczema. A few people with 2q37 deletion syndrome have a rare form of kidney cancer called Wilms tumor. Some affected individuals have malformations of the brain, gastrointestinal system, kidneys, or genitalia.
Most cases of 2q37 deletion syndrome are not inherited. They result from a chromosomal deletion that occurs as a random event during the formation of reproductive cells (eggs or sperm) or in early fetal development. Affected people typically have no history of the disorder in their family.  Rarely, affected individuals inherit a copy of chromosome 2 with a deleted segment from an unaffected parent. In these cases, one of the parents carries a chromosomal rearrangement between chromosome 2 and another chromosome. This rearrangement is called a balanced translocation. No genetic material is gained or lost in a balanced translocation, so these chromosomal changes usually do not cause any health problems. However, translocations can become unbalanced as they are passed to the next generation. Children who inherit an unbalanced translocation can have a chromosomal rearrangement with extra or missing genetic material. Some individuals with 2q37 deletion syndrome inherit an unbalanced translocation that deletes genetic material near the end of the long arm of chromosome 2, which results in birth defects and other health problems characteristic of this disorder.
These resources address the diagnosis or management of 2q37 deletion syndrome:  - Gene Review: Gene Review: 2q37 Microdeletion Syndrome  - Genetic Testing Registry: Brachydactyly-Mental Retardation 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
Congenital mirror movement disorder is a condition in which intentional movements of one side of the body are mirrored by involuntary movements of the other side. For example, when an affected individual makes a fist with the right hand, the left hand makes a similar movement. The mirror movements in this disorder primarily involve the upper limbs, especially the hands and fingers. This pattern of movements is present from infancy or early childhood and usually persists throughout life, without other associated signs and symptoms. Intelligence and lifespan are not affected.  People with congenital mirror movement disorder can have some difficulty with certain activities of daily living, particularly with those requiring different movements in each hand, such as typing on a keyboard. They may experience discomfort or pain in the upper limbs during prolonged use of the hands.  The extent of the mirror movements in this disorder can vary, even within the same family. In most cases, the involuntary movements are noticeable but less pronounced than the corresponding voluntary movements. The extent of the movements typically stay the same throughout the lifetime of an affected individual.  Mirror movements can also occur in people who do not have congenital mirror movement disorder. Mild mirror movements are common during the normal development of young children and typically disappear before age 7. They can also develop later in life in people with neurodegenerative disorders such as Parkinson disease. Mirror movements may also be present in certain other conditions with a wider range of signs and symptoms (syndromes).
Congenital mirror movement disorder can be caused by mutations in the DCC or RAD51 gene; mutations in these genes account for a total of about 35 percent of cases. Mutations in other genes that have not been identified likely account for other cases of this disorder.  The DCC gene provides instructions for making a protein called the netrin-1 receptor, which is involved in the development of the nervous system. This receptor attaches (binds) to a substance called netrin-1, fitting together like a lock and its key. The binding of netrin-1 to its receptor triggers signaling that helps direct the growth of specialized nerve cell extensions called axons, which transmit nerve impulses that signal muscle movement. Normally, signals from each half of the brain control movements on the opposite side of the body. Binding of netrin-1 to its receptor inhibits axons from developing in ways that would carry movement signals from each half of the brain to the same side of the body.  Mutations in the DCC gene result in an impaired or missing netrin-1 receptor protein. A shortage of functional netrin-1 receptor protein impairs control of axon growth during nervous system development. As a result, movement signals from each half of the brain are abnormally transmitted to both sides of the body, leading to mirror movements.  The RAD51 gene provides instructions for making a protein that is also thought to be involved in the development of nervous system functions that control movement, but its role in this development is unclear. Mutations in the RAD51 gene result in a missing or impaired RAD51 protein, but it is unknown how a shortage of functional RAD51 protein affects nervous system development and leads to the signs and symptoms of congenital mirror movement disorder.
In most cases, including those caused by mutations in the DCC or RAD51 gene, 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 altered gene. Some people who have the altered gene never develop the condition, a situation known as reduced penetrance.  Research suggests that in rare cases, this condition may be 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 congenital mirror movement disorder:  - Gene Review: Gene Review: Congenital Mirror Movements  - Genetic Testing Registry: Mirror movements 2  - Genetic Testing Registry: Mirror movements, congenital  - KidsHealth: Occupational Therapy   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
Duane-radial ray syndrome is a disorder that affects the eyes and causes abnormalities of bones in the arms and hands. This condition is characterized by a particular problem with eye movement called Duane anomaly (also known as Duane syndrome). This abnormality results from the improper development of certain nerves that control eye movement. Duane anomaly limits outward eye movement (toward the ear), and in some cases may limit inward eye movement (toward the nose). Also, as the eye moves inward, the eye opening becomes narrower and the eyeball may pull back (retract) into its socket.  Bone abnormalities in the hands include malformed or absent thumbs, an extra thumb, or a long thumb that looks like a finger. Partial or complete absence of bones in the forearm is also common. Together, these hand and arm abnormalities are known as radial ray malformations.  People with the combination of Duane anomaly and radial ray malformations may have a variety of other signs and symptoms. These features include unusually shaped ears, hearing loss, heart and kidney defects, a distinctive facial appearance, an inward- and upward-turning foot (clubfoot), and fused spinal bones (vertebrae).  The varied signs and symptoms of Duane-radial ray syndrome often overlap with features of other disorders. For example, acro-renal-ocular syndrome is characterized by Duane anomaly and other eye abnormalities, radial ray malformations, and kidney defects. Both conditions are caused by mutations in the same gene. Based on these similarities, researchers suspect that Duane-radial ray syndrome and acro-renal-ocular syndrome are part of an overlapping set of syndromes with many possible signs and symptoms. The features of Duane-radial ray syndrome are also similar to those of a condition called Holt-Oram syndrome; however, these two disorders are caused by mutations in different genes.
Duane-radial ray syndrome results from mutations in the SALL4 gene. This gene is part of a group of genes called the SALL family. SALL genes provide instructions for making proteins that are involved in the formation of tissues and organs before birth. The proteins produced from these genes act as transcription factors, which means they attach (bind) to specific regions of DNA and help control the activity of particular genes. The exact function of the SALL4 protein is unclear, although it appears to be important for the normal development of the eyes, heart, and limbs.  Mutations in the SALL4 gene prevent cells from making any functional protein from one copy of the gene. It is unclear how a reduction in the amount of the SALL4 protein leads to Duane anomaly, radial ray malformations, and the other features of Duane-radial ray syndrome and similar conditions.
These resources address the diagnosis or management of Duane-radial ray syndrome:  - Gene Review: Gene Review: SALL4-Related Disorders  - Genetic Testing Registry: Duane-radial ray syndrome  - MedlinePlus Encyclopedia: Skeletal Limb Abnormalities   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
Between 10 and 15 percent of all cases of prion disease are caused by mutations in the PRNP gene. Because they can run in families, these forms of prion disease are classified as familial. Familial prion diseases, which have overlapping signs and symptoms, include familial Creutzfeldt-Jakob disease (CJD), Gerstmann-Strussler-Scheinker syndrome (GSS), and fatal familial insomnia (FFI).  The PRNP gene provides instructions for making a protein called prion protein (PrP). Although the precise function of this protein is unknown, researchers have proposed roles in several important processes. These include the transport of copper into cells, protection of brain cells (neurons) from injury (neuroprotection), and communication between neurons. In familial forms of prion disease, PRNP gene mutations result in the production of an abnormally shaped protein, known as PrPSc, from one copy of the gene. In a process that is not fully understood, PrPSc can attach (bind) to the normal protein (PrPC) and promote its transformation into PrPSc. The abnormal protein builds up in the brain, forming clumps that damage or destroy neurons. The loss of these cells creates microscopic sponge-like holes (vacuoles) in the brain, which leads to the signs and symptoms of prion disease.  The other 85 to 90 percent of cases of prion disease are classified as either sporadic or acquired. People with sporadic prion disease have no family history of the disease and no identified mutation in the PRNP gene. Sporadic disease occurs when PrPC spontaneously, and for unknown reasons, is transformed into PrPSc. Sporadic forms of prion disease include sporadic Creutzfeldt-Jakob disease (sCJD), sporadic fatal insomnia (sFI), and variably protease-sensitive prionopathy (VPSPr).  Acquired prion disease results from exposure to PrPSc from an outside source. For example, variant Creutzfeldt-Jakob disease (vCJD) is a type of acquired prion disease in humans that results from eating beef products containing PrPSc from cattle with prion disease. In cows, this form of the disease is known as bovine spongiform encephalopathy (BSE) or, more commonly, "mad cow disease." Another example of an acquired human prion disease is kuru, which was identified in the South Fore population in Papua New Guinea. The disorder was transmitted when individuals ate affected human tissue during cannibalistic funeral rituals.  Rarely, prion disease can be transmitted by accidental exposure to PrPSc-contaminated tissues during a medical procedure. This type of prion disease, which accounts for 1 to 2 percent of all cases, is classified as iatrogenic.