The third subgroup of MDs described here are the congenital MDs, a heterogeneous group of diseases that include the dystroglycanopathies (caused by mutations in POMT1, POMT2, FKTN, FKRP and other genes), laminin alpha-2 deficiency (CMD 1A), collagen VI-deficient CMD, SEPN1-related CMD, LMNA-related CMD (L-CMD) [49,50,51,52] and the most severe congenital MD, Walker-Warburg syndrome (WWS). The gene discussed is SELENON; the disease is muscular dystrophy-dystroglycanopathy, type A.