Poster presentation, P133

Official XXIst International Pigment Cell Conference website - 21-24 Sept 2011, Bordeaux - France | updated: September 04 2011

Xeroderma Pigmentosum type C: report of a case with multiple melanomas

Xeroderma Pigmentosum (XP) is a rare, autosomal recessive genodermatosis, characterized by DNA repair deficiency, after UV-induced damage, caused by mutations in genes involved in nucleotide excision repair. XP patients have severe photosensitivity and >1000-fold increased incidence of UV-induced cancers at an early age (< 10 years), which are mostly non melanoma skin cancers. Seven complementation groups, XP-A through XP-G, and a variant form (XP-V) have been described. XP type C (XP-C) is caused by biallelic inactivating mutations in the XPC gene involved in global genome repair (GGR). We report the case of a 25-year-old Caucasian male, who presented typical cutaneous features of XP during infancy, and developed multiple skin cancers from age 6. Numerous basal and squamous cell carcinomas developed during childhood, followed from age 23, by multiple melanomas including in situ and invasive profiles. DNA repair analysis, performed at age 15, showed 15% residual activity. XPC gene sequencing evidenced compound heterozygosity for two novel mutations: a nonsense and a missense. The XPC protein, analysed by western blot, was barely detectable. The influence of additional mutations interesting melanoma susceptibility genes is under investigation. The singularities of the present case will be discussed in view of previously published observations. Reference: - Norgauer J, Idzko M, Panther E, Hellstern O, Herouy Y. Xeroderma pigmentosum. Eur J Dermatol. 2003;13(1):4-9. - Blankenburg S, König IR, Moessner R, Laspe P, Thoms KM, Krueger U, Khan SG, Westphal G, Berking C, Volkenandt M, Reich K, Neumann C, Ziegler A, Kraemer KH, Emmert S. Assessment of 3 xeroderma pigmentosum group C gene polymorphisms and risk of cutaneous melanoma: a case-control study. Carcinogenesis. 2005;26(6):1085-90. - Jacobelli S, Soufir N, Lacapere JJ, Regnier S, Bourillon A, Grandchamp B, Hétet G, Pham D, Palangie A, Avril MF, Dupin N, Sarasin A, Gorin I. Xeroderma pigmentosum group C in a French Caucasian patient with multiple melanoma and unusual long-term survival. Br J Dermatol. 2008;159(4):968-73.

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