Relation of D.N.A. repair processes to pathological ageing of the nervous system in xeroderma pigmentosum.

The severity of neurological abnormalities in patients with xeroderma pigmentosum has been found to be related to their ability to repair ultraviolet (U.V.)-damaged D.N.A. Patients with the most severe neurological abnormalities have the least effective D.N.A. repair is shown by the decreased colony-forming ability of their U.V.-irradiated fibroblasts. These results suggest that the lack of adequate D.N.A. repair is causally related to the clinical manifestations of a human heredodegenerative nervous system disease.