SELENON and rigid spine syndrome: Mutations in the selenoprotein N (SEPN1) gene have been identified as the cause of the following four autosomal recessive diseases, which are classified under the title of the SEPN1-related myopathies: rigid spine congenital muscular dystrophy, MmD, CFTD and desmin-related myopathy with Mallory body-like inclusions [88,89].