Missense mutation Thr309Lys in the coagulation factor XII gene in a Spanish family with hereditary angioedema type III

A new type of hereditary angioedema (type III) affecting mainly women with normal C1-inhibitor level and function has been described. Exposition to estrogens is an important precipitating factor. Recently, a missense mutation in the gene of the blood coagulation factor XII (Hageman factor) has been reported in a few families with this type of hereditary angioedema. To study a patient and her family with recurrent swelling attacks during pregnancy. Complement factors C3 and C4 as well as C1-inhibitor level and function were determined. Genomic DNA was isolated from venous blood samples and screened for mutations in the coagulation factor XII gene. C3 and C4 levels as well as C1-inhibitor level and function were normal. A missense mutation Thr309Lys was identified in factor XII gene with a heterozygotic pattern. This mutation was also identified in the mother of the patient, her daughter and her son. These results support that the mentioned mutation in factor XII gene causes hereditary angioedema type III.