CRPPA and neuromuscular disease caused by qualitative or quantitative defects of alpha-dystroglycan: Three dystroglycanopathy genes have been reported to encode key enzymes required for tandem RboP synthesis, namely fukutin12, fukutin-related protein (FKRP)13, and isoprenoid synthase domain-containing protein (ISPD), also known as CRPPA14,15 (Supplementary Fig. 1).