Adult cancer survivors are at increased risk of stroke attributable to treatment related factors such as chemotherapy (e.g., anthracyclines and monoclonal antibodies) and immunotherapy (e.g., selective estrogen receptor modulators and aromatase inhibitors) along with shared lifestyle-related risk factors (e.g., obesity, cigarette smoking, hypertension) between cancer and ischemic stroke5. The gene discussed is ESR1; the disease is obesity due to melanocortin 4 receptor deficiency.