The xeroderma pigmentosum complementation group C (XPC) is one of the eight core genes (i.e., ERCC1, XPA, XPB, XPC, XPD, XPE, XPF, and XPG) in the nuclear excision repair (NER) pathway of the DNA repairing system. The gene discussed is XPC; the disease is Xeroderma pigmentosum complementation group C.