BRCA1 and breast cancer: The Breast Cancer Information Core database (BIC; http://research.nhgri.nih.gov/bic/; version modified September 2010) states that almost 50% of all reported BRCA1 mutations and about 30% of reported BRCA2 mutations are either frameshift or nonsense mutations, thus it is reasonable to expect that protein truncating mutations will be common in any other highly penetrant breast cancer susceptibility genes.