Effects of ionizing radiation on cells from Fanconi's anemia patients.

The lymphocytes from some Fanconi's anemia patients appeared to be more radiosensitive than normal as measured by the number of X-ray-(or bleomycin-) induced chromosome aberrations seen following G2 treatment. Fibroblasts from the same patients, however, all showed the same degree of colony survival as normals following exposure to gamma-rays [Do, 1.13 +/- 0.072 (S.E.) Gy and 1.14 +/- 0.077 Gy for Fanconi's anemia and normal fibroblasts, respectively]. The lack of increased radiosensitivity in Fanconi's fibroblasts was also observed by the same degree of inhibition of DNA synthesis as seen in normals following gamma-irradiation. The results show clearly that there is no increase in radiosensitivity common to all cell types from Fanconi's patients, although an apparent increase in chromosomal radiosensitivity may be seen in the lymphocytes from an occasional patient.