The prevalence of germline BRCA1 or 2 mutations correlated with the extent of ovarian and breast cancer in families and was particularly high (81%) in families containing more than two OC cases and at least one case of BC diagnosed before age 60.24 Extremely high mutation frequencies were also reported in a historical collection of families particularly burdened by breast and ovarian cancer. The gene discussed is BRCA1; the disease is ovarian cancer.