Xeroderma pigmentosum

**Definition:** Xeroderma pigmentosum (XP) is a rare genodermatosis characterised by extreme sensitivity to ultraviolet (UV)-induced changes in the skin and eyes, and multiple skin cancers. It is subdivided into 8 complementation groups, according to the affected gene: XPA to XPG, and XP variant (XPV). The severity of the clinical manifestations and the age of onset are extremely variable and are in part dependent on exposure to sunlight and the complementation group.