title: Hypersensitivity to G2 chromatid radiation damage in familial dysplastic naevus syndrome.
abstract: Skin fibroblasts from 25 members of nine kindreds with familial dysplastic naevus syndrome (DNS), 12 apparently normal spouses, and 11 additional unrelated normal individuals were tested for G2 cell-cycle phase sensitivity to ionising radiation. The cells from individuals with DNS or hereditary cutaneous malignant melanoma with DNS (HCMM/DNS) had significantly more chromatid breaks and gaps when entering metaphase 0.5-1.5 h after G2 phase X-irradiation (1 Gy) than those from unaffected controls. In two cases, the test results positively identified individuals before the clinical diagnosis of DNS. A clinically normal obligate carrier of the HCMM/DNS gene showed the enhanced G2 radiosensitivity. Moreover, in a test on 1 proband, the sensitivity was apparent in peripheral blood lymphoblasts. Enhanced G2 chromatid radiosensitivity may be a marker of genetic susceptibility to HCMM/DNS.
mesh_terms: D000328:Adult; D000368:Aged; D002648:Child; D002842:Chromatids / Q000528:radiation effects*; D004416:Dysplastic Nevus Syndrome / Q000235:genetics*; D005260:Female; D006801:Humans; D007399:Interphase / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D010375:Pedigree