Intravenous pdC1-INH has efficacy in reducing the duration and intensity of attacks of angioedema in patients with HAE nC1-INH (as shown by non-controlled, retrospective studies on small case series recruited with non-predetermined homogeneous criteria) despite the fact that the pathogenesis of the angioedema, by definition, is not caused by a deficiency in C1-INH [15, 40, 41, 45]. The gene discussed is COL18A1; the disease is hereditary angioedema.