ACE2 and COVID-19: A recently published genome-wide association study across more than 50,000 COVID-19 patients and more than 700,000 noninfected individuals revealed a rare variant that was associated with downregulated ACE2 expression and reduced risk of COVID-19 (Horowitz et al., 2021), providing additional evidence for the importance of ACE2 for SARS-CoV-2 infection in humans.