SELENOS and muscular dystrophy-dystroglycanopathy, type A: The genetic defects affect different proteins with essential roles in muscle development and function: defects of structural proteins (laminin-α2, collagen, integrin, and plectin), defects of glycosylation (Walker-Warburg syndrome, muscle-eye brain disease, and Fukuyama CMD), proteins of the endoplasmic reticulum and nucleus (selenoprotein, selenocysteine insertion sequence-binding protein 2, laminin A/C), and mitochondrial membrane protein (choline kinase beta).