The present disclosure provides for compositions comprising a chimeric polypeptide comprising a polypeptide effective for treating glycogen storage disease and an internalizing moiety that promotes delivery into cells. In certain embodiments, the polypeptide effective for treating glycogen storage disease is an acid alpha-glucosidase (GAA), a laforin, an amyloglucosidase (AGL), a malin, or an alpha amylase. The present disclosure also provides for methods for decreasing glycogen accumulation in cells or for treating glycogen storage diseases, including Forbes-Cori Disease, Andersen Disease, von Gierke Disease, Pompe Disease, and Lafora Disease, comprising administering the chimeric polypeptide disclosed herein.
