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Hereditary angioedema with normal c1 inhibition
1Department of Dermatology, Johannes Gutenberg University, Mainz, Germany. bork@hautklinik.klinik.uni-mainz.de
Current Allergy and Asthma Reports
|August 7, 2009
Summary
Hereditary angioedema (HAE) is now understood to have causes beyond C1 inhibitor deficiency. Research identifies new HAE forms, often linked to factor XII gene mutations, particularly in women.
Area of Science:
- Immunology
- Genetics
- Hematology
Background:
- Hereditary angioedema (HAE) was traditionally linked solely to C1 inhibitor deficiency.
- Recent findings reveal HAE can occur with normal C1 inhibitor levels and protein in plasma.
- This suggests alternative etiologies for HAE.
Purpose of the Study:
- To investigate the expanding understanding of hereditary angioedema beyond C1 inhibitor deficiency.
- To identify genetic and clinical factors associated with HAE in patients with normal C1 inhibitor.
- To explore triggers for HAE symptoms in affected individuals.
Main Methods:
- Case reporting and family studies of hereditary angioedema patients.
- Biochemical analysis of C1 inhibitor activity and protein levels.
- Genetic analysis, including mutation screening of the coagulation factor XII gene.
Main Results:
- Identification of families with HAE presenting normal C1 inhibitor activity and protein.
- HAE symptoms frequently triggered by hormonal factors (oral contraceptives, hormone replacement therapy, pregnancy) in affected women.
- Detection of mutations in the coagulation factor XII (Hageman factor) gene in some HAE families.
Conclusions:
- Hereditary angioedema encompasses forms unrelated to C1 inhibitor deficiency.
- Factor XII gene mutations represent a significant genetic cause for these HAE variants.
- Hormonal influences play a crucial role in symptom manifestation in affected women.
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