Piebaldism with deafness: molecular evidence for an expanded syndrome.

In a South African girl of Xhosa stock with severe piebaldism and profound congenital sensorineural deafness we identified a novel missense substitution at a highly conserved residue in the intracellular kinase domain of the KIT proto-oncogene, R796G. Though auditory anomalies have been observed in mice with dominant white spotting (W) due to KIT mutations, deafness is not typical in human piebaldism. Thus, the occurrence of sensorineural deafness in this patient extends considerably the phenotypic range of piebaldism due to KIT gene mutation in humans and tightens the clinical similarity between piebaldism and the various forms of Waardenburg syndrome.