| arginase deficiency | <biochemistry> Arginase is the fifth enzyme of the urea cycle and catalyses the hydrolysis of arginine to ornithine and urea as the final step in the detoxification of ammonia. Deficiency of the enzyme results in hyperargininaemia and episodic hyperammonaemia, leading to moderate to severe mental retardation and spasticity. at least two isozymes of arginase exist in man. AI (the enzyme deficient in the disorder) is cytosolic and found primarily in liver and red blood cells, whereas AII is mitochondrial and found predominantly in kidney but also to a lesser extent in liver, brain, and other tissues. While AII activity appears to be induced in AI deficiency, it is only partially effective in maintaining urea cycle function. The normal in vivo function of AII is unclear. Arginase deficiency is diagnosed by observing high arginine concentrations on either qualitative or quantitative plasma or urine amino acid analysis. The diagnosis is confirmed by finding markedly decreased or absent arginase activity in an isotopic red blood cell enzymatic assay. The AI gene has been cloned, sequenced, and localised to human chromosome band 6q23. (17 Dec 1997) |
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| ascorbic acid deficiency | A condition due to a dietary deficiency of ascorbic acid (vitamin c), characterised by malaise, lethargy, and weakness. As the disease progresses, joints, muscles, and subcutaneous tissues may become the sites of haemorrhage. Ascorbic acid deficiency frequently develops into scurvy in young children fed unsupplemented cow's milk exclusively during their first year. It develops also commonly in chronic alcoholism. (cecil textbook of medicine, 19th ed, p1177) (12 Dec 1998) |
| beta-d-glucuronidase deficiency | A rare deficiency of beta-d-glucuronidase; an autosomal recessive disorder with several allelic forms, characterised by abnormal mucopolysaccharide metabolism leading to progressive mental deterioration, splenic and hepatic enlargement, and dysostosis multiplex. Synonym: mucopolysaccharidase. (05 Mar 2000) |
| brancher deficiency glycogenosis | Type of glycogen storage disease, due to deficiency of amylo-1,4-1,6-transglucosidase (brancher enzyme). Synonym: brancher deficiency glycogenosis, debrancher deficiency. (05 Mar 2000) |
| calcium deficiency | A low blood calcium (hypocalcaemia) makes the nervous system highly irritable with tetany (spasms of the hands and feet, muscle cramps, abdominal cramps, overly active reflexes, etc.). Chronic calcium deficiency contributes to poor mineralization of bones, soft bones (osteomalacia) and osteoporosis; and, in children, rickets and impaired growth. Food sources of calcium include dairy foods, some leafy green vegetables such as broccoli and collards, canned salmon, clams, oysters, calcium-fortified foods, and tofu. According to the National Academy of Sciences, adequate intake of calcium is 1 gram daily for both men and women. The upper limit for calcium intake is 2.5 grams daily. (12 Dec 1998) |
| carbamoylphosphate synthetase deficiency | <biochemistry> Carbamoylphosphate synthetase is the initial enzyme of the urea cycle, catalysing the synthesis of carbamoylphosphate from ammonia, bicarbonate and ATP as the first step of ammonia detoxification. The enzyme is an intramitochondrial form called CPS I. A different isozyme found in the cytoplasm, called CPS II, is much less active and apparently not involved in the urea cycle. The deficiency state is autosomal recessive and presents in infancy with massive hyperammonaemia and neurologic deficits in survivors. Diagnosis is suggested by the blood biochemistry and confirmed by specific enzyme assay on liver or rectal biopsy. Prenatal diagnosis by molecular methods has been used successfully in informative families. Inheritance: autosomal recessive. (07 Apr 1998) |
| carbonic anhydrase II deficiency syndrome | <syndrome> An inherited deficiency of carbonic anhydrase II that results in osteopetrosis and metabolic acidosis. Synonym: osteopetrosis with renal tubular acidosis. (05 Mar 2000) |
| g-6-p-d deficiency | <biochemistry> An inherited condition that results in a deficiency in glucose-6-phosphate dehydrogenase. Particular drugs (sulphonamides) can exacerbate this problem. The result is haemolytic anaemia. (27 Sep 1997) |
| galactokinase deficiency | An inborn error of metabolism due to congenital deficiency of galactokinase, resulting in increased blood galactose concentration (galactosaemia), cataracts, hepatomegaly, and mental deficiency; autosomal recessive inheritance. Galactose epimerase deficiency and galactose-1-phosphate uridyl transferase deficiency produce much the same clinical picture. (05 Mar 2000) |
| galactokinase deficiency galactosaemia | An autosomal recessive disorder resulting in an accumulation of galactose and galactitol. (05 Mar 2000) |
| magnesium deficiency | Can occur due to inadequate intake or impaired intestinal absorption of magnesium. Low magnesium (hypomagnesaemia) is often associated with low calcium (hypocalcaemia) and low potassium (hypokalaemia). Deficiency of magnesium causes increased irritability of the nervous system with tetany (spasms of the hands and feet, muscular twitching and cramps, spasm of the larynx, etc.). According to the national academy of sciences, the recommended dietary allowances of magnesium are 420 milligrams per day for men and 320 milligrams per day for women. The upper limit of magnesium as supplements is 350 milligrams daily, in addition to the magnesium from food and water. (12 Dec 1998) |
| glucocerebrosidase deficiency | Causes Gaucher's disease (type 1), a progressive genetic disease due to an enzyme defect. The enzyme, glucocerebrosidase, is needed to break down the chemical glucocerebroside. The enzyme defect in persons with Gaucher's disease (GD) leads to the accumulation of glucocerebroside in the spleen, liver, and lymph nodes. The most common early sign is enlargement of the spleen (located in the upper left abdomen). Other signs include low red blood cell counts (anaemia), a decrease in blood clotting cells (platelets), increased pigmentation of the skin, and a yellow fatty spot on the white of the eye (a pinguecula). Severe bone involvement can lead to pain and collapse of the bone of the hips, shoulders, and spine. The GD gene is on chromosome 1. The disease is a recessive trait. Both parents carry a GD gene and transmit it for their child with the disease. The parents' risk of a child with the disease is 1 in 4 with each pregnancy. This type of Gaucher's disease (noncerebral juvenile Gaucher's disease) is most common in Ashkenazi Jews (of European origin) and is the most common genetic disease among Jews in the United States. (12 Dec 1998) |
| glucose-6-dehydrogenase deficiency | <biochemistry> An inherited condition that results in a deficiency in glucose-6-phosphate dehydrogenase. Particular drugs (sulphonamides) can exacerbate this problem. The result is haemolytic anaemia. (27 Sep 1997) |
| cellular immunity deficiency syndrome | <syndrome> A syndrome marked by increased susceptibility to infection, especially to viral infection, associated with defective functioning of the mechanism responsible for acquired immunity of the cell-mediated kind. See: immunodeficiency. (05 Mar 2000) |
| glucose-6-phosphate dehydrogenase deficiency | A deficiency of glucose-6-phosphate dehydrogenase, an enzyme important for maintaining cellular concentrations of reduced nucleotides. Deficiency of this enzyme is the commonest disease-causing enzyme defect in humans affecting an estimated 400 million people. The gene for this enzyme is on the X chromosome and there are various polymorphic forms. Males with the enzyme deficiency develop haemolytic anaemia when red blood cells are exposed to oxidant drugs such as the antimalarial primaquine, the sulfonamide antibiotics or sulfones, naphthalene moth balls, or fava beans. It can also cause anaemia of the newborn, and chronic nonspherocytic haemolytic anaemia. Inheritance: X-linked. (12 Sep 2002) |