Some studies reported a more frequent vascular ACE2 immunoreactivity in various brain regions of COVID-19 patients than in control patients [71, 90], others found it to be more frequent in the frontal cortex of patients with hypertension or dementia compared to controls [84] suggesting that brain parenchymal vascular ACE2 expression may depend on the underlying pathological condition. This evidence concerns the gene ACE2 and COVID-19.