As ACE2, a key receptor protein involved in SARS-CoV-2 infectivity, also degrades kinins and bradykinin excess, it has been hypothesized to play a pathologic role in the severe respiratory complications of COVID-19 and individuals with HAE-C1INH have been hypothesized to be at increased risk for SARS-CoV-2 infection and complications [63]. This evidence concerns the gene SERPING1 and COVID-19.