Increased radiosensitivity of skin fibroblasts in Friedreich's ataxia

Fibroblasts from forearm skin biopsy specimens from 3 patients with Friedreich's ataxia and controls without evidence of hypersensitivity to ionising radiation were exposed to a range of doses of gamma or x-rays up to 550 rad, and cell survival was measured by counting clones derived from single fibroblasts. Cells from two of the three Friedreich cases were found to have an abnormally low survival at the dose levels used, the difference from controls run in parallel being significant. These findings suggest the possibility of defective DNA repair processes in at least some patients with Friedreich's ataxia.