DAG1 and neuromuscular disease caused by qualitative or quantitative defects of alpha-dystroglycan: To date, mutations in 14 genes [4–18], all coding for putative or demonstrated glycosyltransferase, have been associated with muscular dystrophies (referred to as secondary dystroglycanopathies) [19], while only a couple of cases have been associated with mutations in DAG1, the gene that encodes both α-dystroglycan and β-dystroglycan [20, 21].