A few highly penetrant genetic variants, like those in BRCA1 and BRCA2 genes, have been proved to increase breast cancer risk5,6; although their low prevalence hardly allows them to explain around 5% cases of breast cancer7, carrying any of these variants puts women in such a high risk that screening practices have been adapted in carrier women and even oophorectomy or early mastectomy can be considered in some cases in the absence of breast cancer diagnosis8. Here, BRCA1 is linked to breast cancer.