Therefore, the expression of ACE2 and TMPRSS2 is assumed to be associated with host susceptibility to and severity of COVID-19 (Bunyavanich et al., 2020; Devaux et al., 2020; Saheb Sharif-Askari et al., 2020; Sharif-Askari et al., 2020; Wu et al., 2020). The gene discussed is ACE2; the disease is COVID-19.