SERPING1 and hereditary angioedema: The pathophysiology of HAE primarily involves dysregulation of the contact activation system due to deficiency or dysfunction of C1 inhibitor (C1INH), a serine protease inhibitor encoded by the SERPING1 gene location (GRCh38) is 11:57,597,685–57,614,848 at 11q12.1 (2, 3).