Piebaldism is a rare but distinctive disorder associated with a defect in the migration and differentiation of melanoblasts from the neural crest. Piebaldism refers to multi-colored hair and skin. It affects many mammals including humans.
Inheritance: autosomal dominant, with other affected family members
Genetic loci:
(1) 4q12, at the KIT locus (c-kit proto-oncogene), which affects a transmembrane cellular receptor for mast/stem cell growth factor and melanocyte development.
(2) 8q11, at the zinc finger transcription factor SNA12 (SLUG), with reduced production of snail2 protein
Clinical features:
(1) white forelock
(2) symmetrical hypopigmented or depigmented patches over the medial aspects of:
(2a) the forehead
(2b) the eyebrows
(2c) the chin
(2d) ventral chest and abdomen
(2e) extremities
(3) variable patches of hyperpigmented or normally pigmented skin within or at the edges of the hypopigmented areas
(4) variable heterochromia iridis
(5) normal survival
There is normal pigmentation over back, hands and feet.
Exclusions:
(1) albinism
(2) vitiligo
(3) poliosis circumscripta
(4) Waardenburg syndrome
