COL18A1 and hereditary angioedema: It is noteworthy that at least 90% of HAE-nC1-INH cases are women and the exacerbation episodes are strikingly dependent on additional exogenous estrogens (Binkley and Davis, 2000), and there are cases with variants affecting the F12 function that are estrogen dependent (Prieto-García et al., 2017).