Excision repair of DNA in some photodermatoses.

Excision repair of DNA was measured in a number of photosensitive subjects by estimating unscheduled DNA synthesis in cultured fibroblasts after ultraviolet radiation. The amount of unscheduled DNA synthesis and the action spectrum for this process were estimated in each subject and compared with seven normal subjects. Two subjects with polymorphic light eruption and three with actinic reticuloid exhibited normal levels of DNA repair and normal action spectra. In one subject with classical xeroderma pigmentosum no excision repair could be demonstrated whilst in another the amount of repair was lower than normal. The finding of normal DNA excision repair in polymorphic light eruption does not support an earlier claim that this repair process is abnormal in this common photodermatosis.