Elevated chromosome aberration frequency after X-ray exposure of cultured fibroblasts derived from patients with porokeratosis.

Porokeratosis (PK) is a rare genetic skin disorder inherited as an autosomal dominant trait and regarded as a disease predisposing to cancer. To evaluate chromosomal radiosensitivity of PK cells, we examined chromosome aberration frequency after X-irradiation of cultured skin fibroblasts derived from PK patients and controls. Without X-ray exposure, frequencies of chromosome-type aberrations (exchanges or deletions) were not different between the patients and controls. Following X-ray irradiation, frequencies of deletions in the patient group were significantly increased, whereas those of exchanges were not elevated. No differences in chromatid-type aberration frequency were found between the patients and controls with or without exposure to X-ray. The observed radiosensitivity, though not as high as in ataxia telangiectasia (AT) cells, agrees well with the previously reported higher radiosensitivity of PK fibroblasts in survival analysis.