SELENON and neuromuscular disease caused by qualitative or quantitative defects of alpha-dystroglycan: The most common forms are dystroglycanopathies (DGP; 12–25%), Collagen 6 related disorders (COL6-RD) (12–19%), laminin-alpha 2 related dystrophies (LAMA2-RD; 10–37%), and selenoprotein N related myopathy (SEPN1-RM; 11.65%).