BRCA1 and Hereditary breast and ovarian cancer syndrome: For hereditary breast and ovarian cancer (HBOC) predisposition, clinical genetic testing has focused primarily on the two major predisposing genes: BRCA1 and BRCA2 (BRCA1/2). The identification of a germline disease-causing variant, also called “pathogenic variant”, in the index case of an HBOC family (i.e., the first ascertained patient) allows her/his relatives to benefit from predictive testing and to receive genetic counselling and preventive medical management [1].