HAE has been classified into different types: HAE with C1 inhibitor deficiency (HAE-C1-INH) resulting from variants in the SERPING1 gene encoding C1-INH and HAE with normal C1-INH (HAE-nC1-INH), which includes variants in F12,3,4PLG,5ANGPT1,6MYOF,7KNG1,8 or HS3ST6. 9Although the association with genetic variant(s) has been identified for some families, the genetic causes in many patients with HAE-nC1-INH are unknown. Here, SERPING1 is linked to C1 inhibitor deficiency.