The updated age-specific distributions of tumour ER and TN status for six of the BC susceptibility genes in the model (PALB2, CHEK2, ATM, BARD1, RAD51C and RAD51D) should allow better differentiation between PVs that may be present in a family and provide age-specific and gene-specific mutation carrier probabilities consistent with the prevalence of PVs observed in Mavaddat et al. 19 We note, however, that estimates are more uncertain at very young and very old ages, where the data are sparse, and more extensive validation may be required in these age-groups. The gene discussed is CHEK2; the disease is breast cancer.