piebaldism

Patchy absence of the pigment of scalp hair, giving a streaked appearance; patches of vitiligo may be present in other areas due to absence of melanocytes; often transmitted as an autosomal dominant trait caused by mutation in the KIT protooncogene on 4q and may be associated with neurologic defects [MIM*172850] or eye changes [MIM*172870]. Cf.:Waardenburg syndrome. SYN: cutaneous albinism, piebald skin, piebaldness.

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pie·bald·ism (piґbawld-iz-əm) a congenital, autosomal dominant pigmentary disorder in which there are patches of white skin and hair that lack melanocytes, with a characteristic distribution pattern that favors the central anterior trunk, mid-extremities, central forehead, and midfrontal portion of the scalp. There is usually a white forelock. It is often due to mutation in the KIT gene (locus: 4q11-q12), a proto-oncogene that encodes a member of the tyrosine kinase family of transmembrane receptors found on the surface of melanocytes.

Hypopigmented epidermal patches and white forelock characteristic of piebaldism.