We previously synthesized a high-resolution CRISPR library targeting 833 genes implicated in SARS-CoV-2 biology (35) based on their identification in prior CRISPR screens of SARS-CoV-2 cytopathic effect (23, 24, 26, –, 30, 36), human genome-wide association studies of COVID-19 susceptibility (37), RNA-seq analysis of genes whose expression correlated with the SARS-CoV-2 receptor ACE2 (38), and our own genome-wide CRISPR screen for modifiers of ACE2 abundance (35). The gene discussed is ACE2; the disease is COVID-19.