Syndrome, Waardenburg

An hereditary disorder characterized by hearing impairment, a white forelock (a frontal white blaze of hair), a difference of color between the iris of one eye and the other (heterochromia iridis), white eye lashes, wide-set inner corners of the eyes, and wide bridge of the nose. Premature graying of the hair may occur and depigmented areas of skin may be present. The severity of Waardenburg syndrome (WS) can vary greatly, and some affected persons escape deafness. The white forelock may be present at birth and later disappear. Waardenburg syndrome is inherited as an autosomal dominant trait in which the heterozygous state (with one copy of the gene) is sufficient to cause the syndrome. The homozygous form of WS with two copies of the gene is a very severe (and fortunately rare) disorder with very severe upper-limb defects that has been called the Klein-Waardenburg syndrome. The gene for classic Waardenburg syndrome, symbolized WS1, has been mapped to chromosome 2 (in band q35) and is at what is called the PAX3 gene locus.