WFS1 and hereditary optic atrophy: Loss-of-function mutations in WFS1 are known to cause autosomal-recessive Wolfram syndrome, a severe neurodegenerative disease mainly characterized by juvenile-onset diabetes mellitus and optic atrophy (OMIM#222300), whereas dominant pathogenic variants in WFS1 were found to cause isolated sensorineural hearing loss (SNHL), syndromic SNHL, congenital cataracts, or early onset diabetes mellitus [7-9].