Median C4 and C1INHq levels were markedly reduced in patients with HAE-C1INH-Type1, with values of 10.1 mg/dL (range: 6.0–27.9) and 8.88 mg/dL (range: 3.8–14.9), respectively (Figures 1, 2). This evidence concerns the gene C4A and hereditary angioedema.