The NER pathway involves several proteins, including those encoded by the XPA, XPC, and ERCC2 (XPD) genes, mutations in each of which can cause a form of XP.9, 10, 11 As discussed by Melis et al., NER – and a role for XP-C – have also been implicated in the repair of DNA oxidative damage.12 The gene discussed is ERCC2; the disease is xeroderma pigmentosum.