Glycogen storage disorder Type Ia (GSD1a) occurs when the body is missing an enzyme that is needed for the liver to convert sugar from its storage form (glycogen) to the form that can be used by the body to produce energy (glucose).  People affected with GSD1a cannot maintain their blood glucose levels and develop hypoglycemia (low blood sugar) within a few hours after eating.  GSD1a can be detected by routine newborn screening which is done in most medical centers.

The gene for GSD1a is located on chromosome #17. Approximately one in 71 individuals of Ashkenazi Jewish descent is a carrier of a mutation in the gene for GSD1a.

Treatment for GSD1a involves providing the body with an outside supply of glucose on a continual basis. If left untreated, affected individuals will develop seizures, enlarged liver, slow growth and short stature.