Xeroderma pigmentosum (XP) patients exhibited several neurological symptoms such as microcephaly, mental retardation and deafness, which are linked to mutations in genes such as XPA, XPB, XPD, XPF, and XPG that are involved in nucleotide excision repair (NER) [39]. Here, ERCC2 is linked to xeroderma pigmentosum.