Type III Glycogenosis

Abstract

A 43-year-old man with an eight-month history of muscular weakness and wasting was found to have an abnormal electromyographic study with muscle biopsy demonstrating glycogen storage. Laboratory studies revealed a diabetic glucose tolerance curve and elevated serum glutamic oxaloacetic transaminase, creatine phosphokinase, lactic dehydrogenase activities. Galactose and glycerol tolerance was normal, while epinephrine and glucagon failed to elevate blood glucose. No elevation of blood lactic acid followed ischemic exercise. Muscle enzyme assay demonstrated the absence of amylo-1, 6-glucosidase activity, and electron microscopic studies revealed subsarcolemmal and intrasarcoplasmic accumulations of glycogen. The clinical, electromyographic, laboratory, and morphologic findings in our patient are compared with previous reports of type III glycogenosis and with other glycogenoses characterized by muscle storage. Among patients with type III glycogenosis three have been mentioned, but not fully reported, with similar weakness and wasting.