Taking into account its involvement in bradykinin production and function, C1 inhibitor deficiency was linked to the pathophysiology of angioedema (Cicardi et al. 2014) and it was hypothesized that it was involved in SARS-CoV-2-elicited angioedema events (Grewal et al. 2020; Belbézier et al. 2021; Szilágyi et al. 2023; Grumach et al. 2021). The gene discussed is SERPING1; the disease is hyperinsulinemic hypoglycemia, familial, 4.