XPC and xeroderma pigmentosum: Among the 68 known XPC mutations causing XP, almost all of these Maghrebi XP-C patients in our cohort bear the founder XPC homozygous mutation: c.1643_1644 delTG; p.Val548AlafsX572 (called later delTG), two patients have heterozygotes delTG mutation and two patients have a different XPC mutation (Supplementary Table S1).