1. ¹Laboratory of Tissue Engineering and Cutaneous Physiopathology, Istituto Dermopatico dell'Immacolata, IRCCS, Via dei Monti di Creta 104, Rome, Italy
2. ²Division of Medical Genetics, San Paolo School of Medicine, University of Milan, Milan, Italy
3. ³6th Division of Dermatology, Istituto Dermopatico dell'Immacolata, IRCCS, Via dei Monti di Creta 104, Rome, Italy

Correspondence: Dr Liliana Guerra, Laboratory of Tissue Engineering and Cutaneous Physiopathology, Istituto Dermopatico dell'Immacolata, IDI-IRCCS, Via dei Castelli Romani 83/85, 00040 Pomezia (Roma), Italy. E-mail: l.guerra@idi.it

⁴These authors contributed equally to this work

Received 19 July 2006; Revised 30 September 2006; Accepted 4 October 2006; Published online 23 November 2006.

Abstract

Piebald trait leukoderma results from "loss-of-function" mutations in the kit gene. Correlations between mutation type and clinical phenotype have been reported. However, mutation classification has been mainly based on the clinical features of patients. The aim of this study was to get a better understanding of the pathogenesis of human piebaldism by establishing whether the kit mutation type may affect the in vitro survival/proliferation of patient melanocytes. Overall, the research was finalized to implement the clinical application of the autologous cultured epidermis in the treatment of piebald patients. Seven patients, who were transplanted with autologous in vitro reconstituted epidermis, showed an average percentage of repigmentation of 90.7. Six novel and one previously reported mutations were found and their postulated effects discussed in relation to the clinical phenotype and in vitro behavior of epidermal cells. Although mutation type did not impair repigmentation given by autotransplantation, it was shown to influence the survival/proliferation of co-cultured melanocytes and keratinocytes. In particular, tyrosine kinase domain mutations were found with melanocyte loss and keratinocyte senescence during expansion of epidermal cultures. Results indicate that the clinical application of cultured epidermis in piebald patients may be optimized by investigating mutation functional effects before planning surgical operations.