Breast cancer accounted for almost a quarter of tumors in our series, and most genes in which deleterious variants were detected are breast CPGs, many of which are not routinely tested in the UK. Pathogenic variants in ATM and CHEK2 are associated with moderate risks,32, 33 and these genes had not been tested by the referring center in any of the individuals with P/LP variants. Six probands had pathogenic variants in PALB2, a gene initially thought to confer moderate risk34 but subsequently reported to have a penetrance somewhere between that of moderate- and high-risk genes such as BRCA1 and BRCA2.35