Germline variants in several other susceptibility genes also confer a high risk of breast cancer, including pathogenic variants in ATM, BARD1, BLM, BRIP1, CDH1, CHEK2, PALB2, PMS2, FAM175A, FANCC/‐M, and RAD51B/‐C/-D as well as the more syndromic predisposing genes; TP53 (Li–Fraumeni syndrome), PTEN (Cowdens disease), STK11 (Peutz‐Jeghers syndrome), NF1 (Neurofibromatosis), and CDH1 (Hereditary diffuse gastric cancer syndrome). This evidence concerns the gene CHEK2 and breast cancer.