Several explanations for severe COVID-19 in adolescents have been proposed.3,20 The more mature binding ability of the SARS-CoV-2 viral receptor (angiotensin-converting enzyme 2), the fewer restrictions on activities that increase exposure to SARS-CoV-2, and the higher incidences of adverse effects and comorbidities resulting from more intensive chemotherapy (eg, lower absolute lymphocyte count, obesity, and diabetes) in older patients than in younger patients may play roles. The gene discussed is ACE2; the disease is diabetes mellitus.