Comparative study of x-ray and UV induced cytotoxicity, DNA repair, and mutagenesis in Down's syndrome and normal fibroblasts.

Utilizing six age-matched human fibroblast cell strains (three normal and three Down's syndrome) cytotoxicity, DNA repair, and X-ray mutagenesis were measured. There was no significant difference in the colony-forming ability after ultraviolet (UV) or X-irradiation between normal and Down's fibroblasts. Similarly, UV-induced unscheduled DNA synthesis was not significantly different between normal and Down's cells. Finally, a comparison between the spontaneous and X-ray induced mutation frequency at the hypoxanthine-guanine phosphoribosyl transferase locus demonstrated no difference between the two cell types (normal and Down's).