Regardless of the loophole that allowed central viral invasion, once inside, the virus seems to lock the door behind and bury its portal of entry by downregulating ACE2 [100], leaving the brain deprived of the neuroprotective ACE2 activity, mimicking what was demonstrated in a mouse model of Alzheimer’s disease (AD) [101]. The gene discussed is ACE2; the disease is early-onset autosomal dominant Alzheimer disease.