Mutations in SEPN1 have been associated with three autosomal recessive congenital myopathies, including rigid spine muscular dystrophy, multiminicore disease and desmin-related myopathy with Mallory body-like inclusions.
Our first objective was to determine whether SEPN1 gene mutations are a cause of congenital fiber-type disproportion (CFTD), a rare form of congenital myopathy in which relative hypotrophy of type 1 (slow twitch) muscle fibers is the principal abnormality on histology.
Mutations in SEPN1 cause selenoprotein N (SEPN)-related myopathy (SEPN-RM) characterized by early-onset axial and neck weakness, spinal rigidity, respiratory failure and histopathological features, ranging from mild dystrophic signs to a congenital myopathy pattern with myofibrillar disorganization.
Selenoprotein N (SELENON) is an endoplasmic reticulum (ER) protein whose loss of function leads to a congenital myopathy associated with insulin resistance (SEPN1-related myopathy).