Efficacy of cornstarch therapy in type III glycogen-storage disease

Type III glycogen-storage disease (GSD-III), due to decreased activity of the glycogen debranching enzyme amylo-1,6 glucosidase, may cause hepatic dysfunction, growth failure, and myopathy. The prevention of hypoglycemia by nocturnal intragastric formula infusion has been shown to enhance growth and improve the metabolic abnormalities associated with GSD-III. Cornstarch therapy was effective in preventing hypoglycemia in a few patients with GSD-III who were previously treated with nocturnal enteral formula infusion, but oral cornstarch had not been evaluated as an initial treatment. We studied three patients with GSD-III who exhibited growth failure, elevated serum aminotransferase concentrations, and asymptomatic hypoglycemia. Cornstarch therapy was associated with maintenance of normoglycemia, increased growth velocity, and decreased serum aminotransferase concentrations in all patients. Our experience suggests that cornstarch therapy can be effective as an initial treatment for patients with GSD-III.