COL18A1 and hereditary angioedema: Another study sequenced the exonic and regulatory regions (5′-UTR and 3′-UTR) of F12 gene from 161 C1-INH-HAE and 191 HAE-nC1-INH, and found 6 F12 polymorphisms in patients with C1-INH-HAE and 9 in patients with HAE-nC1-INH, including rare and first described variants (103).