The response of cells from patients with Huntington's chorea to mutagen-induced chromosome damage.

Abstract

Cultured blood lymphocytes from 15 patients with Huntington's chorea (HC) and matched controls were exposed to a series of graded doses of mitomycin C and ethyl methane sulphonate and examined for the incidence of sister chromatid exchange (SCE). The spontaneous SCE levels did not differ between HC patients and controls and although cells from the majority of HC patients showed a slightly enhanced response to SCE induction by the mutagens, the enhancement was small and significant only on the pooled data. Cultures from 4 HC patients and controls were exposed to a graded series of X-ray exposures and no difference was observed in the spontaneous aberration frequencies between HC cells and controls, or in their response to aberration induction by X-rays. Skin fibroblast cultures derived from three HC patients, two xeroderma pigmentosum patients and two healthy controls were exposed to MMC and the levels of unscheduled DNA synthesis determined. There was no difference between the response of HC cells and normal controls, although such synthesis in the xeroderma cells was severely depressed. It is concluded that: (i) fibroblasts and lymphocytes from HC patients show a normal response to the three mutagens studied; (ii) there is no evidence for any defect in processes involved in repairing the lesions induced; (iii) the slightly elevated response of HC lymphocytes to SCE induction may reflect the presence of a different proportion of a slightly more sensitive T cell sub-set in HC patients, and (iv) HC cells do not show a hypersensitivity to mutagens that could be used as a basis for diagnosis.