Glycogen storage disease II, also known as Pompe disease (OMIM # 232300), is an autosomal recessive disorder caused by the deficiency of the enzyme alpha-glucosidase (see GSD pathway diagram). Alpha-glucosidase deficiency results in the accumulation of significant amounts of glycogen in lysosomes of the affected tissue. Three distinct phenotypes exist for glycogen storage disease II including an infantile form, a juvenile form, and an adult form. Correlations do exist between the age of onset, the clinical severity of the disease, and the residual enzyme activity. Mutations in the GAA gene (OMIM # 606800) cause glycogen storage disease II.

Our collection of glycogen storage disease II cell lines came from twenty-seven individuals, twenty-one of whom are affected with the disease. Of the twenty-one affected individuals, twelve exhibit the infantile form, two exhibit the juvenile form, and the remaining seven have the adult form. Twelve of the individuals have identified mutations in one or both alleles of the GAA gene representing a total of thirteen different mutations (see mutations currently listed in the NIGMS catalog).