ABSENCE OF LINKAGE TO THE ATAXIA-TELANGIECTASIA LOCUS IN FAMILIAL BREAST-CANCER

Heterozygotes for ataxia-telangiectasia (AT) are known to have an incr eased risk of breast cancer. The gene (or genes) responsible for almos t all cases of AT has been localised to chromosome 11q by genetic link age analysis. To examine the possibility that AT heterozygosity may ac count for a substantial proportion of familial breast cancer, we have typed five markers on chromosome 11q in 16 breast cancer families. We have found no evidence for linkage between breast cancer and chromosom e 11q markers and conclude that the contribution of AT to familial bre ast cancer is likely to be minimal.