Variant classification remains a critical challenge to fully realize the clinical utility of genetic testing for ATM. This important issue and others have been identified as areas of priority by the International Consortium on ATM and Cancer, initiated in 2019, which brings together researchers and clinicians who aim to use a collaborative, multidisciplinary approach to addressing key questions about the cancer risks for carriers of a pathogenic ATM variant [12]. The gene discussed is ATM; the disease is cancer.