SERPING1 and Airway obstruction: It is defined by the quantitative and/or functional deficiency of C1 esterase inhibitor (C1-INH), or with normal C1-INH and alteration in genes encoding Hageman factor XII (FXII) of the blood coagulation cascade.1, 2It leads to edema attacks in the skin and submucosa, in the regions of the face, extremities, genitalia, oropharynx, larynx, tongue, airway and gastrointestinal tract with risk of death from airway obstruction.1, 2