Genetic therapy of Xeroderma Pigmentosum: analysis of strategies and translation

Introduction: Xeroderma Pigmentosum (XP) is among the rare genetic disorders remaining without any cure. XP patients bear mutations in one of the eight genes involved in either the repair or the tolerance of DNA lesions induced following UV irradiation by the mechanism of nucleotide excision or of translesion synthesis. Irrespective of their appurtenance to either the classical groups of genetic complementation (XP-A to XP-G), or to the variant form of the disease (XP-V), all patients clinically diagnosed as "X" present with severe photo sensitivity and a high susceptibility toward aggressive skin cancers. Areas covered: Only few palliative 'treatments' can currently be proposed to these patients, among which sun avoidance remains the most efficient recommendation to prevent onset of skin cancers. Early clinical and genetic diagnosis is essential to optimize the care of XP patients. Attempts to genetically correct XP cells by retrovirus-mediated gene transfer have been successful, and held promises for ex vivo cutaneous gene therapy of XP cells using retrovirus-mediated transfer of the therapeutic (XP) gene. Expert commentary: However, bona fide genetic correction by recent techniques of genome edition, for instance using the CRISPR-CAS 9 technology, may appear even more attractive in the future. Taking into account the different facets of the disease in its different forms, we discuss the potential therapeutic approaches that could help improving life conditions of those rare patients who still lack any efficient cure.