The present invention is directed to chimeric polypeptides comprising an amytoglucasklase (AGL) polypeptide mid an internalizing moiety, or chimeric polypeptides comprising a mature acid-alpha glucosidase (GAA) and an internalizing moiety. The chimeric polypeptides of the invention are used to increase the activity of She enzyme in cells, decrease glycogen accumulation in cells and treat Forbes-Cori disease.