SARS-CoV-2 may induce downregulation of ACE2 by a number of mechanisms including: (1) decreased ACE2 receptor expression due to immune dysfunction; (2) enhanced shedding of membrane-bound ACE2; and (3) endocytosis of ACE2 receptor with SARS-CoV-2 [34]. The gene discussed is ACE2; the disease is immune system disorder.