Unilateral and asymmetric hearing loss in a Waardenburg Syndrome Type 2 (WS2) pedigree was reported to be caused by mutation in KIT or KITLG. KIT-KITLG signaling pathway and MITF were suggested to mutually interact in the migration process of melanocyte from the neural crest to stria vascularis (SV). The gene discussed is KITLG; the disease is Waardenburg syndrome type 2.