CHEK2 and breast cancer: This study confirms that BOADICEA remains a valid decision-making aid for determining which individuals to offer genetic testing for PVs in BC/OC susceptibility genes after the expansion of the model to include the effects of protein-truncating PVs in CHEK2, ATM, PALB2, BARD1, RAD51C and RAD51D. The calibration was most optimal at predicted carrier probabilities around ten to twenty percent, however, with evidence of underestimation at lower carrier probabilities and overestimation at higher carrier probabilities.