WFS1 and Werner syndrome: More than 200 variants in the WFS1 gene are responsible for WS type 1, which represents 99% of WS cases, while <1% are due to variants in CISD2 gene.3, 4, 5WFS1 encodes a putative 890-amino acid protein, Wolframin, localized into the endoplasmic reticulum (ER) membrane.6