SERPING1 and hereditary angioedema: Although it is widely recognized that the fundamental abnormality in HAE is the uncontrolled activation of the plasma contact system, primarily due to deficient functional C1-INH [1], there is no conclusive evidence that the concentration or functionality of C1-INH is significantly correlated with disease severity or activity, as demonstrated by our previous analyses of Chinese HAE patients [21, 22, 23].