FKTN and neuromuscular disease caused by qualitative or quantitative defects of alpha-dystroglycan: Previous studies on skeletal muscle [19] have found that patients with severe dystroglycanopathy phenotypes do not always have less α-DG glycosylation than milder phenotypes when assessed using immunohistochemical studies on skeletal muscle biopsies, especially for FKRP and FKTN, although there is a broad correlation for POMT1, POMT2, and POMGNT1.