In Thompson et al., the authors performed exome sequencing of multiple breast cancer cases from a small number of families (33 persons in 15 families) in whom BRCA1 and BRCA2 mutations had been excluded, and they focused on mutations that are predicted to ablate the function of the gene product, namely, mutations that cause premature termination of translation or that destroy splice-sites. This evidence concerns the gene BRCA2 and breast cancer.