,39 Furthermore, it is important to distinguish HAE-C1INH from clinically similarly presenting acquired angioedema conditions (eg, acquired angioedema due to C1INH deficiency, acquired angiotensin-converting enzyme inhibitor–associated angioedema, idiopathic histaminergic angioedema, and idiopathic nonhistaminergic angioedema) to enable family screening of patients with HAE as recommended by international guidelines.9 Here, SERPING1 is linked to acquired angioedema.