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).
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.
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 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.