Two novel splicing mutations in the XPA gene in patients with group A xeroderma pigmentosum

Xeroderma pigmentosum (XP) is an autosomal recessive human disease characterized by extreme sensitivity to sunlight resulting in a high incidence of skin cancer and frequent neurological abnormalities. Cells from XP patients are hyper-sensitive to the lethal effect of ultraviolet (UV) radiation because they have a defective DNA repair system (1). There are eight genetic forms of XP, complementation groups A-G have defects in excision repair, while the XP variants is thought to have impaired post-replication repair (2). The causative genes for groups A, B, C, D and G XP have been already identified (3-7). We have cloned a cDNA for the human DNA repair gene that complements the defect of group A XP cells and named it the XP group A (XPA) gene. The human XPA gene codes a protein of 273 amino acids with a zinc finger domain which is important for DNA repair activity of the XP