Adult forms of glycogenosis type II

Abstract

The activity of acid α-glucosidase in cultured fibroblasts from adult patients with the lysosomal storage disease glycogenosis type II is only 10% of normal. A normal activity per molecule is found for the mature as well as for the precursor form of acid α-glucosidase in adult mutant fibroblasts. Excessive lysosomal breakdown of mature enzyme purified from mutant fibroblasts and taken up by acceptor cells does not occur. However, the NH₄Cl-stimulated secretion of a precursor form of acid α-glucosidase by adult mutant fibroblasts is markedly reduced. The results are indicative of a defect during the production of acid α-glucosidase.