| gaucher's disease, type 1 | A progressive genetic disease caused by a defect in an enzyme. The enzyme, called 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) |
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| Recklinghausen's disease type I | type 2 neurofibromatosis |
| mating type gene | Genes that, in Saccharomyces cerevisiae specify into which of the two mating types (a and _) a particular cell falls. Only unlike mating type haploids will fuse. The interest derives from the way in which mating type is switched, the existing gene is removed and a new gene, derived from a (silent) master copy elsewhere in the genome is spliced in. Later this gene will in its turn be replaced by a new copy of the old gene, also derived from a silent master. The a and _ genes code for pheromones that affect cells of the opposite mating type. Similar mating type genes are known from other yeasts and the switching mechanism (cassette mechanism) may be used more generally. (18 Nov 1997) |
| viral hepatitis type A | A virus disease with a short incubation period (usually 15 to 50 days), caused by hepatitis A virus, a member of the family Picornaviridae, often transmitted by faecal-oral route; may be inapparent, mild, severe, or occasionally fatal and occurs sporadically or in epidemics, commonly in school-age children and young adults; necrosis of periportal liver cells with lymphocytic and plasma cell infiltration is characteristic and jaundice is a common symptom. Synonym: epidemic hepatitis, hepatitis A, infectious hepatitis, MS-1 hepatitis, short incubation hepatitis, virus A hepatitis. (05 Mar 2000) |
| viral hepatitis type B | A virus disease with a long incubation period (usually 50 to 160 days), caused by hepatitis B virus, a DNA virus and member of the family Hepadnoviridae, usually transmitted by injection of infected blood or blood derivatives or by use of contaminated needles, lancets, or other instruments; clinically and pathologically similar to viral hepatitis type A, but there is no cross-protective immunity; HBsAg is found in the serum and the hepatitis delta virus occurs in some patients. Synonym: hepatitis B, serum hepatitis, transfusion hepatitis, virus B hepatitis. (05 Mar 2000) |
| viral hepatitis type C | Principal cause of non-A, non-B posttransfusion hepatitis caused by an RNA virus that may be related to Flaviviridae family. Synonym: hepatitis C, virus C hepatitis. (05 Mar 2000) |
| viral hepatitis type D | Acute or chronic hepatitis caused by the hepatitis delta virus, a defective RNA virus requiring HBV for replication. The acute type occurs in two forms: 1) coinfection, the simultaneous occurrence of hepatitis B virus and hepatitis delta virus infections, which usually is self-limiting; 2) superinfection, the appearance of hepatitis delta virus infection in a hepatitis B virus carrier, which often leads to chronic hepatitis The chronic type appears to be more severe than other types of viral hepatitis. Synonym: delta hepatitis, hepatitis D. (05 Mar 2000) |
| viral hepatitis type E | Hepatitis caused by a nonenveloped, single-stranded, positive-sense RNA virus 27-34 nm in diameter, unrelated to other hepatitis; it is the principal cause of enterically transmitted, waterborne, epidemic NANB hepatitis occurring primarily in Asia and Africa. Synonym: hepatitis E. (05 Mar 2000) |
| central Recklinghausen's disease type II | type 1 neurofibromatosis |
| central type neurofibromatosis | Type I neurofibromatosis. Incomplete neurofibromatosis, multiple neurofibromas with minimal manifestations, perhaps limited to cafe-au-lait spots; individuals with minimal lesions may have offspring with severe involvement. Synonym: abortive neurofibromatosis. (05 Mar 2000) |
| glycogen storage disease type I | <disease> An autosomal recessive disease in which gene expression of glucose-6-phosphatase is absent, resulting in hypoglycaemia due to lack of glucose production. Accumulation of glycogen in liver and kidney leads to organomegaly, particularly massive hepatomegaly. Increased concentrations of lactic acid and hyperlipidemia appear in the plasma. Clinical gout often appears in early childhood. Inheritance: autosomal recessive. (12 Dec 1998) |
| glycogen storage disease type II | <disease> Glycogenosis due to alpha-1,4-glucosidase (acid maltase) deficiency. It affects muscle, heart, and other organs. (12 Dec 1998) |
| glycogen storage disease type IV | <disease> An autosomal recessive metabolic disorder due to a deficiency in expression of branching enzyme (alpha-1,4-glucan-6-alpha-glucosyltransferase), resulting in an accumulation of abnormal glycogen with long outer branches. Clinical features are muscle hypotonia and cirrhosis. Death from liver disease usually occurs before age 2. Inheritance: autosomal recessive (12 Dec 1998) |
| glycogen storage disease type V | <disease> Glycogenosis due to muscle phosphorylase deficiency. Characterised by painful cramps following sustained exercise. Inheritance: autosomal recessive (12 Dec 1998) |
| glycogen storage disease type VI | <disease> A hepatic glycogen storage disease in which there is an apparent deficiency of hepatic phosphorylase activity. However, studies have not been able to distinguish between phosphorylase deficiency and phosphorylase kinase deficiency in patients with hepatic glycogenosis. (12 Dec 1998) |