Disturbances in α-dystroglycan glycosylation, which impair binding to LG domain-containing extracellular ligands including laminin, underlie a collection of genetic disorders known as α-dystroglycanopathies (Jimenez-Mallebrera et al., 2005). This evidence concerns the gene DAG1 and neuromuscular disease caused by qualitative or quantitative defects of alpha-dystroglycan.