Historically, treatment options for HAE have included stimulating endogenous C1 INH synthesis using attenuated androgens, reducing C1 INH consumption with protease inhibitors (e.g. transexamic acid), and replacing C1 INH with fresh frozen plasma or C1 INH (plasma derived or recombinant); plasma derived C1 INH being the prefered option for acute attacks for the last 30 years [9]. This evidence concerns the gene SERPING1 and hereditary angioedema.