Breast cancer (BC) risk is significantly associated with pathogenic variants in at least eight susceptibility genes: BRCA1 (MIM#113705), BRCA2 (MIM#600185), PALB2 (MIM#610355), ATM (MIM#607585), CHEK2 (MIM# 604373), BARD1 (MIM#601593), RAD51C (MIM#602774), and RAD51D (MIM#602954) [9, 10]. The gene discussed is ATM; the disease is breast cancer.