Among HAE-nC1INH patients, a proportion of cases bear heterozygous variants in the F12, PLG, ANGPT1, or KNG1 genes resulting in HAE-FXII, HAE-PLG, HAE-ANGPT1, and HAE-KNG1 disease variants, respectively (Maas and López-Lera, 2019). This evidence concerns the gene KNG1 and hereditary angioedema.