A novel mutation in the XPA gene results in two truncated protein variants and leads to a severe XP/neurological symptoms phenotype.

BACKGROUND: The nucleotide excision repair (NER) pathway repairs UV-induced DNA lesions in an accurate fashion and prevents UV-irradiated areas of the skin from tumour formation. The XPA protein plays a major role in DNA damage demarcation as well as stabilization of other NER factors and was found to be defective in xeroderma pigmentosum (XP) complementation group A patients. OBJECTIVE: Characterization of four new XP-A patients. METHODS: Genomic and cDNA sequencing, post-UV cell survival of living cells, host-cell reactivation of patients' fibroblasts and Western blotting. RESULTS: One of the four investigated patients shows a novel mutation leading to two different truncated protein variants. Three patients contain the already described p.R228X mutation. All patient cell lines exhibit a strong UVC sensitivity and reduced NER capability. In most of the cases stable protein expression was detected. CONCLUSION: We discovered four new XP-A patients and a novel XPA mutation resulting in two diverse patient alleles.