Mutations in POMK that inhibit phosphorylation of the GalNAc-β3-GlcNAc-β4-Man linked to α-dystroglycan alter the ability of α-dystroglycan to bind to the extracellular matrix protein, laminin, leading to congenital and limb-girdle muscular dystrophies [21]. Here, DAG1 is linked to limb-girdle muscular dystrophy.