DAG1 and muscular dystrophy: Muscular dystrophy-dystroglycanopathies constitute a clinically heterogeneous group of muscular dystrophies that arise from primary (DAG1 (OMIM 128239), which encodes dystroglycan), secondary (genes participating in the maturation of glycans on α-dystroglycan), or tertiary (genes involved in the fabrication of the carbohydrate building blocks) genetic defects associated with the processing and functionality of α-dystroglycan1,2.