Mutations in SRY (sex-determining region Y)-box10 (SOX10) gene on chromosome 22q13.1 are associated with WS2E (OMIM: 611,584) which occurs in about 15 % of WS2 and also mutations in the snail homolog of 2 (SNAI2) gene, mapped to chromosome 8q11.21, result in WS2D (OMIM: 608,890). The gene discussed is SNAI2; the disease is Waardenburg syndrome type 2.