Only recently (2009) has the US Food and Drug Administration approved other modalities/formulations (plasma-derived human C1-INH, plasma kallikrein inhibitor, C1-INH concentrates, nanofiltered plasma-derived human C1-INH, and bradykinin B2 receptor antagonist) for treating HAE attacks only [10]. Here, BDKRB2 is linked to hereditary angioedema.