Reporting the results of cystic fibrosis carrier screening.

The recent discovery of the cystic fibrosis gene has offered the possibility of population-based cystic fibrosis carrier screening. Although > 100 distinct mutations have been identified, five of these in aggregate represent about 85% of the alleles in Britain and the United States. Screening programs that test for these five mutations can be designed to offer several alternative ways to communicate the risk to a pregnancy and several alternative ways to manage a pregnancy. At this time we favor a strategy of screening partners in a couple in sequence, screening the second partner only if the first is positive; nevertheless, different strategies will appeal to different couples.