Complete BRCA1 andBRCA2 mutation analysis is a time consuming and expensive process. Many laboratories have chosen to screen only those parts of the genes with a high yield of mutations: exons 2, 11, and 20 in BRCA1 and exons 10 and 11 inBRCA2. While this may be a valid approach in optimising use of scarce resources, it is a somewhat self fulfilling prophesy on the location of most mutations. Furthermore, most institutions use the protein truncation test (PTT) to analyse the large exon 11 in both genes and exon 10 in BRCA2. PTT will not detect missense mutations (possibly a blessing given the difficulty in establishing their effect), but also mutations at the extreme of each exon will be missed, as they will not produce a recognisably different …