The viral spike (S) glycoprotein of both SARS-CoV and SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) as a receptor to mediate cell entry [2,3], while MERS mediates infection by binding to the dipeptidyl peptidase 4 (DPP4) [4]. The gene discussed is DPP4; the disease is infection.