Improvements in sequencing technology and multigene panel testing have increased the likelihood of detecting these cancer-predisposing variants in not only high-penetrance genes such as BRCA1/2, PALB2, CDH1, PTEN and TP53 but in moderate penetrance genes as well (i.e., ATM, CHEK2 and NF1). High penetrance genes confer a 5- to 20-fold lifetime increased risk of breast cancer and moderate penetrance genes confer a 1.5- to 5-fold increased risk [7,11,16,19,20]. Here, ATM is linked to breast cancer.