Previous studies performed in mice found upregulated protein levels of enzymes involved in glucose uptake and cytoplasmic glycogen synthesis in skeletal muscle from mice with Pompe disease, including glycogenin (GYG1), glycogen synthase (GYS1), glucose transporter 4 (GLUT4), glycogen branching enzyme 1 (GBE1), and UDP‐glucose pyrophosphorylase (UGP2) suggesting a positive feedforward loop for cellular glycogen accumulation.13, 14. Here, GYS1 is linked to glycogen storage disease II.