Confirmed cases of C4BP deficiency have not yet been reported in humans. Only one human case has been reported of the primary C4BP deficiency in a patient with disease clinically resembling Behçet’s disease with angioedema (69), but it is not clear whether the complete disease was associated with C4BP deficiency or just the angioedema. The gene discussed is C4BPA; the disease is hyperinsulinemic hypoglycemia, familial, 4.