WFS1 and Leber hereditary optic neuropathy: Wolframin (WFS1) is a transmembrane ER resident protein encoded by the WFS1 gene that in a mutant form causes Wolfram syndrome 1 (WS1), an autosomal recessive degenerative disease characterized by insulin-dependent diabetes mellitus, optic atrophy, deafness and various neurological symptoms (Hofmann et al., 2003).