bowang0911/MedQuAD huggingface dataset:
Hypermethioninemia is an excess of a particular protein building block (amino acid), called methionine, in the blood. This condition can occur when methionine is not broken down (metabolized) properly in the body.  People with hypermethioninemia often do not show any symptoms. Some individuals with hypermethioninemia exhibit intellectual disability and other neurological problems; delays in motor skills such as standing or walking; sluggishness; muscle weakness; liver problems; unusual facial features; and their breath, sweat, or urine may have a smell resembling boiled cabbage.  Hypermethioninemia can occur with other metabolic disorders, such as homocystinuria, tyrosinemia and galactosemia, which also involve the faulty breakdown of particular molecules. It can also result from liver disease or excessive dietary intake of methionine from consuming large amounts of protein or a methionine-enriched infant formula.
Mutations in the AHCY, GNMT, and MAT1A genes cause hypermethioninemia.  Inherited hypermethioninemia that is not associated with other metabolic disorders can be caused by shortages (deficiencies) in the enzymes that break down methionine. These enzymes are produced from the MAT1A, GNMT and AHCY genes. The reactions involved in metabolizing methionine help supply some of the amino acids needed for protein production. These reactions are also involved in transferring methyl groups, consisting of a carbon atom and three hydrogen atoms, from one molecule to another (transmethylation), which is important in many cellular processes.  The MAT1A gene provides instructions for producing the enzyme methionine adenosyltransferase. This enzyme converts methionine into a compound called S-adenosylmethionine, also known as AdoMet or SAMe. The GNMT gene provides instructions for making the enzyme glycine N-methyltransferase. This enzyme starts the next step in the process, converting AdoMet to a compound called S-adenosyl homocysteine, or AdoHcy. The AHCY gene provides instructions for producing the enzyme S-adenosylhomocysteine hydrolase. This enzyme converts the AdoHcy into the compound homocysteine. Homocysteine may be converted back to methionine or into another amino acid, cysteine.  A deficiency of any of these enzymes results in a buildup of methionine in the body, and may cause signs and symptoms related to hypermethioninemia.
Hypermethioninemia can have different inheritance patterns. This condition is usually inherited in an autosomal recessive pattern, 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.  Hypermethioninemia is occasionally inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In these cases, an affected person usually has one parent with the condition.
These resources address the diagnosis or management of hypermethioninemia:  - Baby's First Test  - Genetic Testing Registry: Glycine N-methyltransferase deficiency  - Genetic Testing Registry: Hepatic methionine adenosyltransferase deficiency  - Genetic Testing Registry: Hypermethioninemia with s-adenosylhomocysteine hydrolase deficiency   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
Chylomicron retention disease is an inherited disorder that affects the absorption of dietary fats, cholesterol, and certain fat-soluble vitamins. As food is digested after a meal, molecules called chylomicrons are formed to carry fat and cholesterol from the intestine into the bloodstream. Chylomicrons are also necessary for the absorption of certain fat-soluble vitamins, such as vitamin E and vitamin D. A lack of chylomicron transport causes severely decreased absorption (malabsorption) of dietary fats and fat-soluble vitamins. Sufficient levels of fats, cholesterol, and vitamins are necessary for normal growth and development.  The signs and symptoms of chylomicron retention disease appear in the first few months of life. They can include failure to gain weight and grow at the expected rate (failure to thrive); diarrhea; and fatty, foul-smelling stools (steatorrhea). Other features of this disorder may develop later in childhood and often impair the function of the nervous system. Affected people may eventually develop decreased reflexes (hyporeflexia) and a decreased ability to feel vibrations.
Mutations in the SAR1B gene cause chylomicron retention disease. The SAR1B gene provides instructions for making a protein that is involved in transporting chylomicrons within enterocytes, which are cells that line the intestine and absorb nutrients.  SAR1B gene mutations impair the release of chylomicrons into the bloodstream. A lack of chylomicrons in the blood prevents dietary fats and fat-soluble vitamins from being used by the body, leading to the nutritional and developmental problems seen in people with chylomicron retention disease.
Neuromyelitis optica is an autoimmune disorder that affects the nerves of the eyes and the central nervous system, which includes the brain and spinal cord. Autoimmune disorders occur when the immune system malfunctions and attacks the body's own tissues and organs. In neuromyelitis optica, the autoimmune attack causes inflammation of the nerves, and the resulting damage leads to the signs and symptoms of the condition.  Neuromyelitis optica is characterized by optic neuritis, which is inflammation of the nerve that carries information from the eye to the brain (optic nerve). Optic neuritis causes eye pain and vision loss, which can occur in one or both eyes.  Neuromyelitis optica is also characterized by transverse myelitis, which is inflammation of the spinal cord. The inflammation associated with transverse myelitis damages the spinal cord, causing a lesion that often extends the length of three or more bones of the spine (vertebrae). In addition, myelin, which is the covering that protects nerves and promotes the efficient transmission of nerve impulses, can be damaged. Transverse myelitis causes weakness, numbness, and paralysis of the arms and legs. Other effects of spinal cord damage can include disturbances in sensations, loss of bladder and bowel control, uncontrollable hiccupping, and nausea. In addition, muscle weakness may make breathing difficult and can cause life-threatening respiratory failure in people with neuromyelitis optica.  There are two forms of neuromyelitis optica, the relapsing form and the monophasic form. The relapsing form is most common. This form is characterized by recurrent episodes of optic neuritis and transverse myelitis. These episodes can be months or years apart, and there is usually partial recovery between episodes. However, most affected individuals eventually develop permanent muscle weakness and vision impairment that persist even between episodes. For unknown reasons, approximately nine times more women than men have the relapsing form. The monophasic form, which is less common, causes a single episode of neuromyelitis optica that can last several months. People with this form of the condition can also have lasting muscle weakness or paralysis and vision loss. This form affects men and women equally. The onset of either form of neuromyelitis optica can occur anytime from childhood to adulthood, although the condition most frequently begins in a person's forties.  Approximately one-quarter of individuals with neuromyelitis optica have signs or symptoms of another autoimmune disorder such as myasthenia gravis, systemic lupus erythematosus, or Sjgren syndrome. Some scientists believe that a condition described in Japanese patients as optic-spinal multiple sclerosis (or opticospinal multiple sclerosis) that affects the nerves of the eyes and central nervous system is the same as neuromyelitis optica.
No genes associated with neuromyelitis optica have been identified. However, a small percentage of people with this condition have a family member who is also affected, which indicates that there may be one or more genetic changes that increase susceptibility. It is thought that the inheritance of this condition is complex and that many environmental and genetic factors are involved in the development of the condition.  The aquaporin-4 protein (AQP4), a normal protein in the body, plays a role in neuromyelitis optica. The aquaporin-4 protein is found in several body systems but is most abundant in tissues of the central nervous system. Approximately 70 percent of people with this disorder produce an immune protein called an antibody that attaches (binds) to the aquaporin-4 protein. Antibodies normally bind to specific foreign particles and germs, marking them for destruction, but the antibody in people with neuromyelitis optica attacks a normal human protein; this type of antibody is called an autoantibody. The autoantibody in this condition is called NMO-IgG or anti-AQP4.  The binding of the NMO-IgG autoantibody to the aquaporin-4 protein turns on (activates) the complement system, which is a group of immune system proteins that work together to destroy pathogens, trigger inflammation, and remove debris from cells and tissues. Complement activation leads to the inflammation of the optic nerve and spinal cord that is characteristic of neuromyelitis optica, resulting in the signs and symptoms of the condition.  The levels of the NMO-IgG autoantibody are high during episodes of neuromyelitis optica, and the levels decrease between episodes with treatment of the disorder. However, it is unclear what triggers episodes to begin or end.
These resources address the diagnosis or management of neuromyelitis optica:  - Genetic Testing Registry: Neuromyelitis optica  - National Institute of Neurological Disorders and Stroke: Neuromyelitis Optica Information Page  - The Transverse Myelitis Association: Acute Treatments   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
Renal tubular dysgenesis is a severe kidney disorder characterized by abnormal development of the kidneys before birth. In particular, kidney structures called proximal tubules are absent or underdeveloped. These structures help to reabsorb needed nutrients, water, and other materials into the blood and excrete everything else into the urine. Without functional proximal tubules, the kidneys cannot produce urine (a condition called anuria).  Fetal urine is the major component of the fluid that surrounds the fetus (amniotic fluid), and anuria leads to decreased amniotic fluid levels (oligohydramnios). Amniotic fluid helps cushion and protect the fetus and plays a role in the development of many organs, including the lungs. Oligohydramnios causes a set of abnormalities called the Potter sequence, which includes distinctive facial features such as a flattened nose and large, low-set ears; excess skin; inward- and upward-turning feet (clubfeet); and underdeveloped lungs.  Renal tubular dysgenesis also causes severe low blood pressure (hypotension). In addition, bone development in the skull is abnormal in some affected individuals, causing a large space between the bones of the skull (fontanels).  As a result of the serious health problems caused by renal tubular dysgenesis, affected individuals usually die before birth, are stillborn, or die soon after birth from respiratory failure. Rarely, with treatment, affected individuals survive into childhood. Their blood pressure usually normalizes, but they quickly develop chronic kidney disease, which is characterized by reduced kidney function that worsens over time.
Mutations in the ACE, AGT, AGTR1, or REN gene can cause renal tubular dysgenesis. These genes are involved in the renin-angiotensin system, which regulates blood pressure and the balance of fluids and salts in the body and plays a role in kidney development before birth.  The renin-angiotensin system consists of several proteins that are involved in a series of steps to produce a protein called angiotensin II. In the first step, the renin protein (produced from the REN gene) converts a protein called angiotensinogen (produced from the AGT gene) to angiotensin I. In the next step, angiotensin-converting enzyme (produced from the ACE gene) converts angiotensin I to angiotensin II. Angiotensin II attaches (binds) to the angiotensin II receptor type 1 (AT1 receptor; produced from the AGTR1 gene), stimulating chemical signaling.  By binding to the AT1 receptor, angiotensin II causes blood vessels to narrow (constrict), which results in increased blood pressure. This protein also stimulates production of the hormone aldosterone, which triggers the absorption of salt and water by the kidneys. The increased amount of fluid in the body also increases blood pressure. Proper blood pressure, which delivers oxygen to the developing tissues during fetal growth, is required for normal development of the kidneys (particularly of the proximal tubules) and other tissues.  Mutations in the ACE, AGT, AGTR1, or REN gene impair the production or function of angiotensin II, leading to a nonfunctional renin-angiotensin system. Without this system, the kidneys cannot control blood pressure. Because of low blood pressure, the flow of blood is reduced (hypoperfusion), and the fetal tissues do not get enough oxygen during development. As a result, kidney development is impaired, leading to the features of renal tubular dysgenesis. Hypoperfusion also causes the skull abnormalities found in individuals with this condition.  Medications that block the activity of the angiotensin-converting enzyme or the AT1 receptor are used to treat high blood pressure. Because these drugs impair the renin-angiotensin system, they can cause an acquired (non-inherited) form of renal tubular dysgenesis in fetuses of pregnant women who take them. Acquired renal tubular dysgenesis can also result from other conditions that cause renal hypoperfusion during fetal development. These include heart problems, congenital hemochromatosis, and a complication that can occur in twin pregnancies called twin-to-twin transfusion syndrome.
Crohn disease is a complex, chronic disorder that primarily affects the digestive system. This condition typically involves abnormal inflammation of the intestinal walls, particularly in the lower part of the small intestine (the ileum) and portions of the large intestine (the colon). Inflammation can occur in any part of the digestive system, however. The inflamed tissues become thick and swollen, and the inner surface of the intestine may develop open sores (ulcers).  Crohn disease most commonly appears in a person's late teens or twenties, although the disease can appear at any age. Signs and symptoms tend to flare up multiple times throughout life. The most common features of this condition are persistent diarrhea, abdominal pain and cramping, loss of appetite, weight loss, and fever. Some people with Crohn disease have chronic bleeding from inflamed tissues in the intestine; over time, this bleeding can lead to a low number of red blood cells (anemia). In some cases, Crohn disease can also cause medical problems affecting the joints, eyes, or skin.  Intestinal blockage is a common complication of Crohn disease. Blockages are caused by swelling or a buildup of scar tissue in the intestinal walls. Some affected individuals also develop fistulae, which are abnormal connections between the intestine and other tissues. Fistulae occur when ulcers break through the intestinal wall to form passages between loops of the intestine or between the intestine and nearby structures (such as the bladder, vagina, or skin).  Crohn disease is one common form of inflammatory bowel disease (IBD). Another type of IBD, ulcerative colitis, also causes chronic inflammation of the intestinal lining. Unlike Crohn disease, which can affect any part of the digestive system, ulcerative colitis typically causes inflammation only in the colon. In addition, the two disorders involve different patterns of inflammation.
Crohn disease is related to chromosomes 5 and 10.  Variations of the ATG16L1, IRGM, and NOD2 genes increase the risk of developing Crohn disease.  The IL23R gene is associated with Crohn disease.  A variety of genetic and environmental factors likely play a role in causing Crohn disease. Although researchers are studying risk factors that may contribute to this complex disorder, many of these factors remain unknown. Cigarette smoking is thought to increase the risk of developing this disease, and it may also play a role in periodic flare-ups of signs and symptoms.  Studies suggest that Crohn disease may result from a combination of certain genetic variations, changes in the immune system, and the presence of bacteria in the digestive tract. Recent studies have identified variations in specific genes, including ATG16L1, IL23R, IRGM, and NOD2, that influence the risk of developing Crohn disease. These genes provide instructions for making proteins that are involved in immune system function. Variations in any of these genes may disrupt the ability of cells in the intestine to respond normally to bacteria. An abnormal immune response to bacteria in the intestinal walls may lead to chronic inflammation and the digestive problems characteristic of Crohn disease.  Researchers have also discovered genetic variations in certain regions of chromosome 5 and chromosome 10 that appear to contribute to Crohn disease risk. One area of chromosome 5, known as the IBD5 locus, contains several genetic changes that may increase the risk of developing this condition. Other regions of chromosome 5 and chromosome 10 identified in studies of Crohn disease risk are known as "gene deserts" because they include no known genes. Instead, these regions may contain stretches of DNA that regulate nearby genes. Additional research is needed to determine how genetic variations in these chromosomal regions are related to a person's chance of developing Crohn disease.
Antiphospholipid syndrome is a disorder characterized by an increased tendency to form abnormal blood clots (thromboses) that can block blood vessels. This clotting tendency is known as thrombophilia. In antiphospholipid syndrome, the thromboses can develop in nearly any blood vessel in the body, but most frequently occur in the vessels of the lower limbs. If a blood clot forms in the vessels in the brain, blood flow is impaired and can lead to stroke. Antiphospholipid syndrome is an autoimmune disorder. Autoimmune disorders occur when the immune system attacks the body's own tissues and organs.  Women with antiphospholipid syndrome are at increased risk of complications during pregnancy. These complications include pregnancy-induced high blood pressure (preeclampsia), an underdeveloped placenta (placental insufficiency), early delivery, or pregnancy loss (miscarriage). In addition, women with antiphospholipid syndrome are at greater risk of having a thrombosis during pregnancy than at other times during their lives. At birth, infants of mothers with antiphospholipid syndrome may be small and underweight.  A thrombosis or pregnancy complication is typically the first sign of antiphospholipid syndrome. This condition usually appears in early to mid-adulthood but can begin at any age.  Other signs and symptoms of antiphospholipid syndrome that affect blood cells and vessels include a reduced amount of blood clotting cells called platelets (thrombocytopenia), a shortage of red blood cells (anemia) due to their premature breakdown (hemolysis), and a purplish skin discoloration (livedo reticularis) caused by abnormalities in the tiny blood vessels of the skin. In addition, affected individuals may have open sores (ulcers) on the skin, migraine headaches, heart disease, or intellectual disability. Many people with antiphospholipid syndrome also have other autoimmune disorders such as systemic lupus erythematosus.  Rarely, people with antiphospholipid syndrome develop thromboses in multiple blood vessels throughout their body. These thromboses block blood flow in affected organs, which impairs their function and ultimately causes organ failure. These individuals are said to have catastrophic antiphospholipid syndrome (CAPS). CAPS typically affects the kidneys, lungs, brain, heart, and liver, and is fatal in over half of affected individuals. Less than 1 percent of individuals with antiphospholipid syndrome develop CAPS.
The exact prevalence of antiphospholipid syndrome is unknown. This condition is thought to be fairly common, and may be responsible for up to one percent of all thromboses. It is estimated that 20 percent of individuals younger than age 50 who have a stroke have antiphospholipid syndrome. Ten to 15 percent of people with systemic lupus erythematosus have antiphospholipid syndrome. Similarly, 10 to 15 percent of women with recurrent miscarriages likely have this condition. Approximately 70 percent of individuals diagnosed with antiphospholipid syndrome are female.
The genetic cause of antiphospholipid syndrome is unknown. This condition is associated with the presence of three abnormal immune proteins (antibodies) in the blood: lupus anticoagulant, anticardiolipin, and anti-B2 glycoprotein I. Antibodies normally bind to specific foreign particles and germs, marking them for destruction, but the antibodies in antiphospholipid syndrome attack normal human proteins. When these antibodies attach (bind) to proteins, the proteins change shape and bind to other molecules and receptors on the surface of cells. Binding to cells, particularly immune cells, turns on (activates) the blood clotting pathway and other immune responses.  The production of lupus anticoagulant, anticardiolipin, and anti-B2 glycoprotein I may coincide with exposure to foreign invaders, such as viruses and bacteria, that are similar to normal human proteins. Exposure to these foreign invaders may cause the body to produce antibodies to fight the infection, but because the invaders are so similar to the body's own proteins, the antibodies also attack the human proteins. Similar triggers may occur during pregnancy when a woman's physiology, particularly her immune system, adapts to accommodate the developing fetus. These changes during pregnancy may explain the high rate of affected females.  Certain genetic variations (polymorphisms) in a few genes have been found in people with antiphospholipid syndrome and may predispose individuals to produce the specific antibodies known to contribute to the formation of thromboses. However, the contribution of these genetic changes to the development of the condition is unclear.  People who test positive for all three antibodies but have not had a thrombosis or recurrent miscarriages are said to be antiphospholipid carriers. These individuals are at greater risk of developing a thrombosis than is the general population.
These resources address the diagnosis or management of antiphospholipid syndrome:  - Genetic Testing Registry: Antiphospholipid syndrome  - Hughes Syndrome Foundation: Diagnosis: How To Get Tested  - Hughes Syndrome Foundation: Treatment and Medication: Current Advice and Information  - National Heart Lung and Blood Institute: How Is Antiphospholipid Antibody Syndrome 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