BRCA1 and Hereditary breast and ovarian cancer syndrome: Of these, 56 were within the group of hereditary breast and ovarian cancer (HBOC) genes with ATM (n = 4), BARD1 (n = 1), BRCA1 (n = 16), BRCA2 (n = 24), CHEK2 (n = 7), PALB2 (n = 3) and RAD51C (n = 1), while 13 were within other known tumor predisposition genes: MLH1 (n = 1), MN1 (n = 1), PMS2 (n = 1) and MUTYH (het) (n = 10).