Previously, Pax3 mutants including Sp, Sp2H and Pax3-Cre mice have been analyzed for cochlear development and those heterozygous mice are identified by the presence of patchy pigmentation of skin hair, which is one of the major phenotypes of type 1 and 3 Waardenburg syndrome patients5,6,9,10,12,23,27. The gene discussed is PAX3; the disease is Waardenburg syndrome.