DAG1 and neuromuscular disease caused by qualitative or quantitative defects of alpha-dystroglycan: Dystroglycanopathies are genetic diseases often arising from the hypoglycosylation of α‐DG and, depending on the affected genes they originate from, they are classified in the following main groups: (a) primary dystroglycanopathies, which occur when mutations of the DAG1 gene alter the state of the DG core protein with potential repercussions on the glycosylation state of α‐DG; (b) secondary dystroglycanopathies, which depend on genetic abnormalities of POMGnT1, POMT1 or LARGE1 among others.