PIK3R4 and dentin dysplasia: We previously demonstrated a correlation between impaired autophagy and myofiber atrophy and weakness in late-onset GSDII.14 Autophagy inhibition also compromises the efficacy of enzyme replacement therapy (ERT), the only available therapy for GSDII.15 In this study, we extended our observation of autophagy impairment in GSDII to DD and investigated the status of two important autophagy regulators: vacuolar protein sorting 15/phosphoinositide-3-kinase regulatory subunit 4 (VPS15/PIK3R4) and transcription factor EB (TFEB).