title: G2 chromosomal radiosensitivity of ataxia-telangiectasia heterozygotes.
abstract: Five lines of skin fibroblasts from individuals heterozygous for ataxia-telangiectasia (A-T), compared with six cell lines from age-matched normal controls, show a much higher frequency of chromatid breaks and gaps following x-irradiation during the G2 phase of the cell cycle. The magnitude of this difference suggests that G2 chromatid radiosensitivity could provide the basis for an assay to detect A-T heterozygotes. Though clinically normal, A-T heterozygotes share a high risk of cancer with A-T homozygotes and constitute approximately 1% of the human population. Further, we propose that G2 chromosomal radiosensitivity, which appears to result from a DNA repair deficiency, may be associated with a genetic predisposition to cancer.
mesh_terms: D001260:Ataxia Telangiectasia / Q000235:genetics* / Q000473:pathology; D002460:Cell Line; D002842:Chromatids / Q000528:radiation effects*; D005347:Fibroblasts / Q000166:cytology / Q000528:radiation effects; D006579:Heterozygote; D006801:Humans; D007399:Interphase / Q000528:radiation effects*; D007621:Karyotyping; D008677:Metaphase; D012867:Skin / Q000473:pathology*