Only a few patients with WS-2 have been reported worldwide; these patients carry recessive mutations in the CISD2 gene (4q24, OMIM #604928), which encodes a small intramembrane protein of the endoplasmic reticulum known as CDGSH iron-sulfur domain-containing protein 2 (CISD2) (15-18). This evidence concerns the gene CISD2 and Waardenburg syndrome type 2.