Clinical profile and mutation analysis of xeroderma pigmentosum in Indian patients

Background: Xeroderma pigmentosum (XP) is an autosomal recessive genetic disorder characterized by cutaneous and ocular photosensitivity and an increased risk of developing cutaneous neoplasms. Progressive neurological abnormalities develop in a quarter of XP patients. Aim: To study the clinical profile and perform a mutation analysis in Indian patients with xeroderma pigmentosum. Methods: Ten families with 13 patients with XP were referred to our clinic over 2 years. The genes XPA, XPB and XPC were sequentially analyzed till a pathogenic mutation was identified. Results: Homozygous mutations in the XPA gene were seen in patients with moderate to severe mental retardation (6/10 families) but not in those without neurological features. Two unrelated families with a common family name and belonging to the same community from Maharashtra were found to have an identical mutation in the XPA gene, namely c.335_338delTTATinsCATAAGAAA (p.F112SfsX2). Testing of the XPC gene in two families with four affected children led to the identification of the novel mutations c.1243C>T or p.R415X and c.1677C>A or p.Y559X. In two families, mutations could not be identified in XPA, XPB and XPC genes. Limitation: The sample size is small. Conclusion: Indian patients who have neurological abnormalities associated with XP should be screened for mutations in the XPA gene.