one and one-half syndrome
| vitamin b 12 deficiency | A nutritional condition produced by a deficiency of vitamin b 12 in the diet, characterised by megaloblastic anaemia. Since vitamin b 12 is not present in plants, humans have obtained their supply from animal products, from multivitamin supplements in the form of pills, and as additives to food preparations. A wide variety of neuropsychiatric abnormalities is also seen in vitamin b 12 deficiency and appears to be due to an undefined defect involving myelin synthesis. (12 Dec 1998) |
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| vitamin B6 deficiency | Member of the water soluble B vitamin group. Vitamin B6 or pyridoxine, is active in the metabolism of proteins, carbohydrates and fats. It is also a necessary part of haemoglobin synthesis. B6 deficiency results in retarded growth and a peripheral neuropathy. (27 Sep 1997) |
| vitamin C deficiency | A disease due to the deficiency of vitamin C (ascorbic acid). Symptoms include weakness, anaemia, spongy gums and mucocutaneous bleeding (mouth ulcers). Synonym: scurvy. (27 Sep 1997) |
| vitamin D deficiency | A vitamin D deficiency disease of infancy or childhood with a disturbance of the normal process of ossification and bone growth. Often manifests with bone deformity. (27 Sep 1997) |
| vitamin e deficiency | A nutritional condition produced by a deficiency of vitamin e in the diet, characterised by posterior column and spinocerebellar tract abnormalities, areflexia, ophthalmoplegia, and disturbances of gait, proprioception, and vibration. In premature infants vitamin e deficiency is associated with haemolytic anaemia, thrombocytosis, oedema, intraventricular haemorrhage, and increasing risk of retrolental fibroplasia and bronchopulmonary dysplasia. An apparent inborn error of vitamin e metabolism, named familial isolated vitamin e deficiency, has recently been identified. (cecil textbook of medicine, 19th ed, p1181) (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) |
| vitamin k deficiency | A nutritional condition produced by a deficiency of vitamin k in the diet, characterised by an increased tendency to haemorrhage (haemorrhagic diathesis). Such bleeding episodes may be particularly severe in newborn infants. (12 Dec 1998) |
| glucosephosphate dehydrogenase deficiency | A disease-producing enzyme deficiency subject to many variants, some of which cause a deficiency of enzyme activity in erythrocytes, leading to haemolytic anaemia. (12 Dec 1998) |
| glucosephosphate isomerase deficiency | <enzyme> An enzyme deficiency characterised by chronic nonspherocytic haemolytic anaemia; autosomal recessive inheritance. Synonym: phosphohexose isomerase deficiency. (05 Mar 2000) |
| glutathione synthetase deficiency | An inborn error of metabolism associated with massive urinary excretion of 5-oxyproline, elevated levels of 5-oxyproline in the blood and cerebrospinal fluid, severe metabolic acidosis, tendency toward haemolysis, and defective central nervous systems function. Glutathione synthetase deficiency has been reported as a generalised condition or with a deficiency restricted to erythrocytes. (05 Mar 2000) |
| mental deficiency | Subnormal intellectual functioning which originates during the developmental period and is associated with impairment of one or more of the following: (1) maturation, (2) learning, (3) social adjustment. (12 Dec 1998) |
| riboflavin deficiency | A dietary deficiency of riboflavin causing a syndrome chiefly marked by cheilitis, angular stomatitis, glossitis associated with a purplish red or magenta-coloured tongue that may show fissures, corneal vascularization, dyssebacia, and anaemia. (12 Dec 1998) |
| choline deficiency | A condition produced by a deficiency of choline in animals. Choline is known as a lipotropic agent because it has been shown to promote the transport of excess fat from the liver under certain conditions in laboratory animals. Combined deficiency of choline (included in the b vitamin complex) and all other methyl group donors causes liver cirrhosis in some animals. Unlike compounds normally considered as vitamins, choline does not serve as a cofactor in enzymatic reactions. (12 Dec 1998) |