The repair of DNA single strand breaks in human cells with genetical disorders.

The aim of this work was to make a preliminary examination of some hereditary diseases, related to precocious aging in order to determine whether the defects involved resulted from an impairment of the DNA repair capacity. To test for an impairment in DNA single strand capacity, in cells from patients with different diseases, we have followed the rate of the DNA after X-irradiation by sedimentation on alkaline sucrose gradients. It was found that all cells observed from Lesh Nyhan, cystic fibrosis, trisomy 15 et 21, retinoblastoma, were able to repair the single strand breaks in their DNA to the same extent and at the same initial rate.