ACE2 and COVID-19: ACE2 is a type I transmembrane protein with wide distribution in many tissues including testes, heart, kidney, liver, intestines, lungs, brain, and oral mucosa (Tipnis et al., 2000; Hamming et al., 2004; Paizis et al., 2005; Doobay et al., 2007; Fan et al., 2020; Xu et al., 2020) which underpins multi-organ manifestation of COVID-19.