glycogen storage diseasemedical dictionary

<hepatology> A group of inherited metabolic disorders involving the enzymes responsible for the synthesis and degradation of glycogen. In some patients, prominent liver involvement is presented. In others, more generalised storage of glycogen occurs, sometimes with prominent cardiac involvement.

Synonyms: glycogenosis

(12 Sep 2002)

glycogen storage disease type Imedical dictionary

<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 IImedical dictionary

<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 IIImedical dictionary

<disease>

An autosomal recessive metabolic disorder due to deficient expression of amylo-1,6-glucosidase (one part of the glycogen debranching enzyme system).

The clinical course of the disease is similar to that of glycogen storage disease type I, but milder. Massive hepatomegaly, which is present in young children, diminishes and occasionally disappears with age. Levels of glycogen with short outer branches are elevated in muscle, liver, and erythrocytes. Six subgroups have been identified, with subgroups type IIIa and type IIIb being the most prevalent.

Inheritance: autosomal recessive

(12 Dec 1998)

glycogen storage disease type IVmedical dictionary

<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 Vmedical dictionary

<disease>

Glycogenosis due to muscle phosphorylase deficiency. Characterised by painful cramps following sustained exercise.

Inheritance: autosomal recessive

(12 Dec 1998)

glycogen storage disease type VImedical dictionary

<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)

glycogen storage disease type VIImedical dictionary

<disease>

An autosomal recessive muscle glycogen storage disease in which there is deficient expression of muscle phosphofructokinase activity, resulting in increased concentrations of glucose-6-phosphate and fructose-6-phosphate and low concentrations of fructose-1,6-diphosphate in muscle tissue.

Glycogen storage in muscle is increased, perhaps due to activation of glycogen synthase by accumulated glucose-6-phosphate. It has been proposed that shunting of glucose-6-phosphate and fructose-6-phosphate into the pentose phosphate pathway may result in increased synthesis of purines and pyrimidines, causing hyperuricaemia and gout.

Erythrocytes from patients may show decreased phosphofructokinase activity and 2,3-diphosphoglycerate deficiency. Exercise intolerance is present and severe congenital muscular dystrophy has been reported.

Inheritance: autosomal recessive

(12 Dec 1998)

glycogen storage disease type VIIImedical dictionary

<disease>

An x-linked recessive hepatic glycogen storage disease resulting from lack of expression of phosphorylase-b-kinase activity. Symptoms are relatively mild; hepatomegaly, increased liver glycogen, and decreased leukocyte phosphorylase are present. Liver shrinkage occurs in response to glucagon.

Inheritance: X-linked recessive

(12 Dec 1998)

glycogen synthasemedical dictionary

<enzyme>

<cell biology> An enzyme of the transferase class that catalyses the reaction of udpglucose and (1,4-alpha-d-glucosyl)n to yield udp and 1,4-alpha-d-glucosyl)n+1. The reaction is highly regulated by allosteric effectors, by phosphorylation reactions, and by insulin.

Chemical name: UDPglucose:glycogen 4-alpha-D-glucosyltransferase

Registry number: EC 2.4.1.11

(12 Dec 1998)

glycogen synthase-d phosphatasemedical dictionary

<enzyme>

<cell biology> An enzyme that catalyses the conversion of phosphorylated, inactive glycogen synthase d to active dephosphoglycogen synthase I.

Chemical name: (UDPglucose:glycogen 4-alpha-D-glucosyltransferase-D) phosphohydrolase

Registry number: EC 3.1.3.42

(12 Dec 1998)

glycogen synthetasemedical dictionary

<enzyme>

<cell biology> An enzyme which makes amylose out of glucose molecules (a type of sugar) and attaches them to glycogen (a type of polysaccharide).

(09 Oct 1997)