Although the pathomechanism of HAE-PLG has not been elucidated as yet, there is evidence pointing to bradykinin as the main mediator of edema in this condition; that is, bradykinin-2 receptor antagonist has been effective in shortening acute attacks in several patients (Belbézier et al., 2018; Bork et al., 2018b; Recke et al., 2019). This evidence concerns the gene KNG1 and hereditary angioedema.