Deficiency or dysfunction of serpins, as in some genetic disorders, cause severe clinical disorders: antithrombin III (AT, SERPINC1), alpha‐1‐antitrypsin (A1AT, SERPINA1), complement C1 esterase‐inhibitor (C1INH, SERPING1), and neuroserpin (NSP, SERPINI1) are associated with severe clotting disorders, severe emphysema, angioedema and dementia, epilepsy, and neurodegeneration, respectively. This evidence concerns the gene SERPINI1 and angioedema.