Oestrogen-dependent hereditary angio-oedema with normal C1 inhibitor: description of six new cases and review of pathogenic mechanisms and treatment.

Background:  Hereditary angio-oedema (HAE) is a rare condition in which there is a deficiency in the quantity or activity of C1 inhibitor (C1INH). Recently, an additional type of HAE with no alterations in the levels or the function of C1INH has been reported. It is defined as HAE with normal C1INH, and named type III HAE or oestrogen-dependent HAE. The aim of this study is to describe the clinical and laboratory findings of six new cases of type III HAE and to review the literature about this disease. Methods:  A short description of six women with recurrent angio-oedema is provided. The characteristics of the patients are compared with the previously reported case series in a literature-based review. Results:  The mean age of the patients at onset was 22 years (range 16–30). All of them had angio-oedema attacks during oestrogen-based contraceptive treatment and four reported episodes during pregnancy. Four patients reported a positive past family history. Two of them had experienced episodes of laryngeal oedema. None of the patients responded to corticoids or antihistamines during the attacks. Levels and functional activity of C1INH were within the normal range in all cases. Conclusions:  Clinical and laboratory findings mirror the observations of previous reports of oestrogen-dependent angio-oedema with normal C1INH. This is the first published series of type III HAE in Spain.