Glycogen storage disease type 0 (also known as GSD 0) is a condition caused by the body's inability to form a complex sugar called glycogen, which is a major source of stored energy in the body. GSD 0 has two types: in muscle GSD 0, glycogen formation in the muscles is impaired, and in liver GSD 0, glycogen formation in the liver is impaired.

Mutations in the GYS1 gene cause muscle GSD 0, and mutations in the GYS2 gene cause liver GSD 0. These genes provide instructions for making different versions of an enzyme called glycogen synthase. Both versions of glycogen synthase have the same function, to form glycogen molecules by linking together molecules of the simple sugar glucose, although they perform this function in different regions of the body.

The prevalence of GSD 0 is unknown; fewer than 10 people with the muscle type and fewer than 30 people with the liver type have been described in the scientific literature. Because some people with muscle GSD 0 die from sudden cardiac arrest early in life before a diagnosis is made and many with liver GSD 0 have mild signs and symptoms, it is thought that GSD 0 may be underdiagnosed.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Published Date: January 01, 2014
Published By: National Institutes of Health