The advent of DNA sequencing technologies has enabled the identification of multiple breast cancer-predisposition genes, beyond BRCA1 and BRCA2. Among these, pathogenic variants in CHEK2, along with ATM, seem to be the most prevalent, known to be associated with intermediate lifetime risks for breast cancer [1,2,3], and are therefore considered moderate penetrance genes. The gene discussed is ATM; the disease is breast carcinoma.