[Occurrence and elimination of single- and double-stranded DNA breaks in the fibroblasts of xeroderma pigmentosum patients exposed to gamma radiation].

A defect in ability to rejoin gamma-induced single-strand DNA breaks, earlier found in the lymphocytes of a patient with form II of xeroderma pigmentosum, has been also shown for cultured skin fibroblasts. In successive subcultivation the ability to rejoin DNA breaks gradually increases. Elimination of double-strand DNA breaks occurs with the same fullness and rate as in the cells of patients with classic form of XP and healthy donors. The subcultivation does not influence this process. Possible causes of the phenomena discovered are discussed.