We were most interested to read the report of Gronwald and colleagues suggesting that there was non-random transmission of the mutant BRCA1 gene to female offspring in a Polish cohort.¹ We have undertaken a similar analysis in an English cohort but found no evidence for non-random transmission.

Gronwald et al reported that 61.5% of unaffected female offspring carried the mutant allele and this ratio did not decrease with age (as might be expected from the exclusion of affected females at advancing age). We have analysed the ratio of positive predictive tests in first degree relatives of proven mutation carriers from 284 BRCA1 and BRCA2 families from central and north western England. Like Gronwald et al¹, we excluded women who were affected with cancer or whose daughter was affected as they were potential obligate carriers. We did not include branches of the family where the mutation status of the parent was unknown even if it was a mother with breast or ovarian cancer in a family with a known mutation. This excluded the possibility of including the testing of daughters of potential phenocopies. We did not reach the level of 89% uptake of predictive testing achieved with the daughters of 91 female mutation carriers in …