[Piebaldisme: a rare genodermatosis].

Piebaldism is a rare autosomal dominant genodermatosis. It is due to congenital absence of melanocytes in the affected areas. We report a case. A 5 year old girl born to consanguineous parents and with similar cases in her mother's; she presented since birth achromic lesions on the legs with a steady evolution. clinical examination showed confluent achromic macules and poliosis (A) with no contrast enhancement under Wood lamp and several coffee-with-milk colored spots on the trunk and thighs(B). The diagnosis of piebaldism was made. Piebaldism is a rare genodermatosis. Its incidence is estimated at less than 1/20000 newborns. It is characterized by the congenital absence of melanocytes in the areas affected by mutation of the c-kit gene and by symmetrical achromic macules appeared at birth with a steady and persistent evolution. A white lock of hair on the forehead could be seen in 80% of cases The differential diagnosis includes vitiligo, albinism and Waardenburg syndrome. Associations have been described with neurofibromatosis type I. However, isolated coffee-with-milk colored spots can be observed; as the case of our patient. The treatment is based on split-thickness skin graft. Piebaldism is a rare genodermatosis. This study aims to discuss its clinical aspects and differential diagnoses.