Editor—Germline mutations in theBRCA1 and BRCA2genes are associated with an increased risk of breast and ovarian cancer.1-3 Different patient populations, predominantly with at least some familial aggregation of breast/ovarian cancer, have been screened to estimate the frequency of mutations and identify women for whom mutation analysis should be considered. The prevalence ofBRCA1 and BRCA2gene mutations has been studied in only a few population based series of patients.4-8

We tested for BRCA2 germline mutations in 40 patients diagnosed with breast cancer before the age of 40, unselected for family history of the disease. These patients were drawn from breast cancer patients recruited between 1992 and 1995 in a population based genetic epidemiological case-control study conducted in a region around Heidelberg in Germany.9 The mean age of onset of the disease in the tested population was 33.8 years (range 25-39 years). Written informed consent was obtained from all patients. The 26 coding exons and flanking intronic regions were analysed from genomic DNA using published10 11 or newly designed primers (available on request). Polymerase chain reactions contained 50 ng DNA, 200 mmol/l of each dinucleotide, 1.5-3.0 mmol/l MgCl, 200 nmol/l of each primer, and …