GLYCOGEN STORAGE DISEASE

Glycogen Storage Diseases are inherited metabolic disorders.

A person with a Glycogen Storage Disease (GSD) has an absence or deficiency of one of the enzymes responsible for making or breaking down glycogen in the body.

This is called an enzyme deficiency. The enzyme deficiency causes either abnormal tissue concentrations of glycogen (too much or too little) or incorrectly or abnormally formed glycogen.

Depending on the type of Glycogen Storage Disease a person has, their enzyme deficiency may be important in all parts of the body, or only in some parts of the body, like the liver or muscle.

All types of Glycogen Storage Disease cause the body to either not be able to make enough glucose, or not be able to use glucose as a form of energy. Determining what type of Glycogen Storage Disease a person has (diagnosis) depends on an individual's symptoms.

There are about eleven known types of Glycogen Storage Disease, which are classified by a number, by the name of the defective enzyme, or by the name of the doctor who first described the condition. For example, Glycogen Storage Disease type Ia, caused by a defect in the enzyme glucose-6-phosphatase, was originally known as Von Gierke's Disease, but is also referred to as Glucose-6-Phosphatase Deficiency Glycogen Storage Disease.