DIFFERENCES IN THE LEVELS OF UV REPAIR AND IN CLINICAL SYMPTOMS IN 2 SIBS AFFECTED BY XERODERMA PIGMENTOSUM

UV-repair activity was studied in 2 sibs affected by XP [xeroderma pigmentosum] showing different clinical symptoms. Complementation studies indicated that both patients fit into complementation group A. The levels of UV-induced 3H-thymidine incorporation, in fibroblasts and in lymphocytes, are different in the 2 patients: residual level of repair DNA synthesis in the sister is higher than in the brother. In one of the cell samples analyzed, UDS [unscheduled DNA synthesis] analysis showed that in the sister a low proportion of cells with normal repair synthesis is present.