Type II Glycogenosis: Mobilization of Lysosomal Glycogen

Type II glycogenosis (generalized glycogen storage disease) is a fatal disease of infants characterized by increased concentration of tissue glycogen and deficiency of lysosomal acid α-1,4-glucosidase activity (acid glucosidase). In a three month old negro girl with the clinical features of the disease, the diagnosis was confirmed by needle biopsy of liver, muscle and brain. Glycogen concentration was 7.8% in liver (normal 2.5% - 6.5%), 7.8% in muscle (normal up to 1.5%), and 0.18% in brain (normal up to 0.08%). Acid glucosidase activity was deficient in all tissues. Electron photomicrographs showed the characteristic abnormal lysosomes packed with glycogen in the liver and brain, but relatively few lysosomes in the muscle despite the presence of large amounts of glycogen. Notable was the abundance of abnormal lysosomes in all hepatic sections. An extract of the fungus Aspergillus niger was prepared with a protein concentration of 25 mgm/cc and a specific activity for acid glucosidase of 22 μM of glucose liberated from glycogen/mgm of protein/minute.