Repeated attacks of type III hereditary angioedema with factor XII mutation during pregnancy

In type III hereditary angioedema (HAE type III), the phenotype is the same as type I and type II disease, but the level and function of C1-esterase inhibitor (C1-INH) is normal. Hereditary angioedema type III has been described as an oestrogen-sensitive form because it can be triggered or aggravated by exposure to high oestrogen levels as seen during pregnancy, especially when associated with Factor XII mutation. This case report describes the evolution and management of repeated angioedema attacks during pregnancy in a woman with HAE, with normal levels and function of C1-INH (type III); and a mis-sense mutation of factor XII. The physiopathology and genetic features, the unpredictability of clinical manifestations and the management during pregnancy and delivery are discussed.