HAE can be categorized into 3 different types including HAE with deficit C1-inhibitor levels (HAE-1), HAE with dysfunctional C1-inhibitor (HAE-2), and HAE with normal C1-inhibitor function (HAE nC1-INH) previously referred to as type 3 (Table 1). Here, COL18A1 is linked to hereditary angioedema.