In modern research, the classification of angioedema is based on its etiology, which can be categorized into three types: C1 inhibitor deficiency (C1-INH hereditary angioedema and C1-INH acquired angioedema), factor XII mutation (FXII hereditary angioedema), and angiotensin-converting enzyme inhibitor-induced angioedema (ACEI acquired angioedema) (Ashina et al., 2015; Cicardi et al., 2016). The gene discussed is ACE; the disease is angioedema.