Consistent with the increased susceptibility to SARS-CoV-2 infection, Vis AD cells expressed higher levels of ACE2 mRNA (Fig. 3c) and protein (Fig. 3b) when compared to Sub AD cells, indicating that the difference in the potential of these cells to be infected by SARS-CoV-2 is determined, at least in part, by the abundance of ACE2. This evidence concerns the gene ACE2 and Alzheimer disease.