Glycogen Storage Disease

Disease characteristics
Glycogen storage disease (GSD) is the result of an enzyme defect that normally catalyzes reactions that ultimately convert glycogen compounds to glucose. Enzyme deficiency results in glycogen accumulation in tissues. GSD type Ia, von Gierke disease, is due to glucose-6-phosphatase [G-6-P] deficiency and causes clinically significant end-organ disease with significant morbidity.

Prevalence
Frequency of carriers in Ashkenazi Jewish population is about 1:60 to 1:70 individuals, where there is no known frequency figures for general public.

Mutation
Two common mutations in enzyme G6P can cause GSD Type Ia. These mutations occur at position 83 (R83C) and 347 (Q347X) amino acid sequence of this enzyme.

Testing criteria and symptoms
Being of Ashkenazi Jewish ancestry
Hypoglycemia
Active seizures, specifically hypoglycemic seizures.
Height, weight, bone mass and grip force decreased in one group of GSD 1a patients.
Patients may give a history of kidney stones, gout, or pancreatitis.