[Hereditary angioneurotic edema: a molecular disease caused by a defect in the O-glycosylation of C1 esterase inhibitor (C1-INH)].

A quantitative and qualitative study of neutral and aminosaccharides in C 1-esterase inhibitor (C 1-INH), protein of the complement system, was performed. We observe a mixed glycosylation of the molecule with an N-glycosylated: O-glycosylated chain ratio of 1: 4. The loss of the inhibitory activity of the molecule in hereditary angioedema (O ANH) is associated with an O-glycosylation deficiency which differs according to the two molecular variants: C 1-INH (1 A) and C 1-INH (II) previously described.