The XPE Gene of Xeroderma Pigmentosum, Its Product and Biological Roles

Xeroderma Pigmentosum (XP) is an inheritable genetic disorder in which patients become very sensitive to ultraviolet (UV) light exposure and prone to skin cancer. Its genetics are complex and multiallelic. Based on complementation studies, involving UV sensitivity of fused cells, initially XP was classified in 5 subgroups, XP-A to XP-E. Present studies, however, have discovered that there are at least 8 subgroups, XP-A to XP-G and XPV. Studies of these genes have shown that their products play critical roles in nucleotide excision repair (NER) following DNA damage. XP-E subgroup has been considered to be of the mildest XP forms and their exact roles in NER are not yet clear.