Hypersensitivity of the skin to ultraviolet light-induced freckle-like pigmentation changes. However, in XPE patients, onset is usually delayed until the second or third decade. This results in late diagnosis, and consequently a hugely increased incidence of skin and ocular cancers (basal cell carcinomas, squamous cell carcinomas and melanoma) on sun-exposed areas may follow. Unlike some XP groups, mutations in XPE are not associated with neurological problems.