Wolfram syndrome is an autosomal recessive disorder caused by bi-allelic variants in WFS1, whereas Wolfram-like syndrome is a dominant condition caused by a single heterozygous pathogenic variant in WFS1. This gene encodes for an endoglycosidase H-sensitive protein called wolframin (Inoue et al., 1998) localized to the endoplasmic reticulum (ER) membrane and secretory granules. Here, WFS1 is linked to Wolfram syndrome.