To explain population-based variations in COVID-19 severity, several studies have looked at ACE2 polymorphisms [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35]. This evidence concerns the gene ACE2 and COVID-19.