FKTN and neuromuscular disease caused by qualitative or quantitative defects of alpha-dystroglycan: To date, at least 18 genes, including fukutin, fukutin-related protein (FKRP), isoprenoid synthase domain-containing protein (ISPD), and like-acetylglucosaminyltransferase (LARGE), have been identified as causative genes for dystroglycanopathy (15).