One group represented human ACE2 mutants expressed at low abundance levels roughly 50-fold less than our high abundance level cells (Fig 2A, bottom), as our previous work showed that relatively subtle missense changes of the human ACE2 sequence had little effect on infection by SARS-CoV or SARS-CoV-2 spike pseudotyped viruses when expressed at high abundance levels [3]. The gene discussed is ACE2; the disease is infection.