HAE is generally classified into 3 types: Type 1, characterized by a low level of C1-INH; Type 2, characterized by present but dysfunctional C1-INH; and HAE-nl-C1INH, characterized by normal levels of C1-INH and clinical features that are similar to HAE Types 1 and 2 [1, 2]. Here, SERPING1 is linked to hereditary angioedema.