Radiosensitivity in Huntington's disease: implications for pathogenesis and presymptomatic diagnosis.

Huntington's disease (HD) is a dominantly inherited fatal disorder characterised by premature death of nerve cells. Cultured lymphocyte lines from four patients with HD were abnormally sensitive to the lethal effects of X rays, as were lines from two of five subjects at risk for HD. The hypersensitivity is specific for ionising radiation, since HD lines had normal survival after exposure to ultraviolet radiation. The hypersensitivity, which may reflect an inherited defect in DNA repair, provides the basis for a presymptomatic diagnostic test for the disease.