Twenty-seven people with hereditary angioedema (HAE) due to C1-inhibitor deficiency (HAE-C1-INH), 4 people with HAE with normal C1-INH function (HAE-nC1-INH; with variants in F12 or PLG genes), and 8 healthy volunteers (HVs) provided informed consent. The gene discussed is COL18A1; the disease is hereditary angioedema.