Background: Mutations in XPA (xeroderma pigmentosum group A-complementing protein) are the cause of xeroderma pigmentosum A (XP-A), an autosomal recessive disease that is mainly characterized by a susceptibility to UV-induced skin cancer and in some cases neurological abnormalities. XPA is one of seven XP complementation groups that have been identified. The XP complementation groups represent genes critical to the nucleotide excision repair (NER) pathway. XPA is thought to function in the recognition of DNA damage and as a processivity factor for XPF and XPG.