ERCC4 and xeroderma pigmentosum: Mutations in any of the NER enzyme genes, i.e., XPA, XPB, XPC, XPD, XPE, XPF, XPG, plus an XPV variant (the genetic disease XPV results from mutations in a gene encoding translesional polymerase η), can cause Xeroderma pigmentosum [3,7,129,130].