For example, it has been shown that the nucleotide sequence immediately downstream of the selenocysteine UGA codon in the mRNA of selenoprotein N (SelN), termed selenocysteine redefinition element (SRE), regulates synthesis of a subset of selenoproteins including SelN (90,91), and mutations in this region have been linked to a series of SEPN1-related myopathies (92). This evidence concerns the gene SELENON and myopathy.