Glycogen Storage Disease

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Abstract
Table viii summarizes the distribution of the eighty-nine cases of glycogenosis from which tissues have been available. In three of the types a definite and specific enzymatic lesion has been determined. Type i, due to a deficiency of glucose-6-phosphatase; type iii, a deficiency of the debranching enzyme, amylo-1,6-glucosidase; and type v, a lack of muscle phosphorylase. It is presumed that the branching enzyme, amylo-1,4-←1,6-transglucosidase is diminished in type iv. Although the mechanism responsible for the accumulation of glycogen in type ii is obscure, the defect [See table in the PDF file] must be present in all tissues. It is possible that those patients in group vi who exhibit a diminished level of liver phosphorylase activity might be classified as a separate group; those with moderate levels of glucose-6-phosphatase might be considered to have a mild type i glycogenosis. Although the more lethal the type of glycogenosis the more information is available concerning siblings, the familial nature of the diseases is apparent. That the genetic loci for determining and controlling the formation of glucose-6-phosphatase and amylo-1,6-glucosidase are closely related is suggested by the association of type i and type iii diseases in some siblings and possibly also in single subjects. Manners and Wright have recently divided limit dextrinosis into three subgroups based on the presumed involvement of a trans-α-glucosylase. We have found no evidence of the action of such an enzyme in glycogen degradation; hence, any subdivision of limit dextrinosis seems unwarranted.