However, due to the nuances and difficulty in establishing a diagnosis of HAE-nl-C1-INH, and because confirmatory biomarkers are not readily available,86 management of these patients should be discussed with an HAE specialist before committing to treatment.8 For the purposes of this review, we have focused on patients with HAE-C1-INH because they account for the vast majority of patients with HAE. The gene discussed is SERPING1; the disease is hereditary angioedema.