Previous analyses have indicated that ATM missense variants within the FRAP-ATM-TRRAP (FAT) and phosphatidylinositol 3-kinase (PI3K) domains were specifically associated with increased BC risk.5 6 We found evidence for increased risk for variants in both these domains (combined OR=1.71; 95% CI 1.12 to 2.61, p=0.015), but estimates did not differ significantly from those for the aggregate of all rare missense variants (Pdiff=0.31). This evidence concerns the gene TRRAP and breast cancer.