B4GAT1 and neuromuscular disease caused by qualitative or quantitative defects of alpha-dystroglycan: To model mild forms of dystroglycanopathy, we examined mice expressing missense mutations in B4gat1 (β–1,4-glucuronyltransferase, B4gat1M155T) and Fkrp (fukutin related protein, FkrpP448L), two genes required for Dystroglycan glycosylation.