Since the ACE2 gene is located on the X chromosome, the high male mortality rate in COVID-19 patients has been hypothesized to be related to the lower levels of ACE2 gene expression in male patients, so much so that the restoration of SARS-CoV-2-induced RAS imbalance has been suggested as an ideal clinical approach to slow the early progression of COVID-19 pathogenesis [11]. Here, ACE2 is linked to COVID-19.