The Subgroups of Type III Glycogenosis

The concentration and the structure of glycogen, and the activity of amylo-1,6-glucosidase have been determined in liver and muscle biopsies of 45 patients affected by type III glycogenosis. Amylo-1,6-glucosidase was measured by the formation of glucose from a phosphorylase limit dextrin (overall reaction), by the incorporation of [14C]glucose into glycogen, by the (1,4 → 1,4) transfer of an oligoglucan and by the hydrolysis of singly branched oligosaccharides. 34 cases were classified as type III A on the basis of a complete or nearly complete inactivity of the enzyme in the two tissues whatever the method used for its detection. 11 cases were characterized by an important residual activity of amylo-1,6-glucosidase which could be detected in the liver or in the muscle and by only some of the methods used.