An Introductory Word to the Section on Hereditary Angioedema — MUDr. Roman Hakl, Ph.D.
Hereditary angioedema (HAE) is a genetically conditioned disease, currently classified into HAE with C1 inhibitor deficiency (HAE-C1-INH), referred to as HAE-I and HAE-II, and HAE with normal level and function of C1 inhibitor (HAE nC1-INH), also referred to as HAE-III (1).
Although HAE is classified among congenital immunodeficiencies, it stands out from this group of diseases by its clinical manifestations. Unlike most others, it does not clinically present with a higher risk of developing infectious diseases. The clinical manifestation of HAE involves swelling of the subcutaneous tissue and mucous membranes due to uncontrolled activation of the complement system. During an attack, virtually any tissue can be affected, resulting in a very broad clinical manifestation of the disease.
A patient with HAE may visit doctors of various specializations due to their clinical difficulties. Therefore, it is crucial for colleagues to keep this diagnosis in mind and, if HAE is suspected, to refer the patient to one of the 4 specialized centers. These are drug centers related to this diagnosis, established at the immunological departments of university hospitals: the Institute of Immunology at the 2nd Medical Faculty of Charles University and Motol University Hospital, the Institute of Clinical Immunology and Allergology at the Medical Faculty of Charles University and University Hospital Hradec Králové, the Institute of Immunology and Allergology at the Medical Faculty of Charles University and University Hospital Plzeň, and the Institute of Clinical Immunology and Allergology at the Medical Faculty of Masaryk University and St. Anne's University Hospital in Brno.
The role of the broader medical community is key in identifying potential patients with HAE. We still encounter cases where patients are misdiagnosed for years and undergo numerous—even invasive—examinations without uncovering the reason. This leads to diagnostic delays, associated with specific risks.
The prevalence of HAE-C1-INH in the population is generally reported as 1:50,000 (ranging from 1:10,000 to 150,000), regardless of race or gender (1). The estimated prevalence of HAE in the Czech Republic is 1:54,000 (2). The prevalence of HAE nC1-INH is estimated to range from 1:100,000 to 400,000 (3–5). In the Czech Republic, we have 180 patients with this diagnosis, indicating that undiagnosed individuals with HAE may still be present in our population.
The case report of a pediatric patient by Assoc. Prof. MUDr. Pavlína Králíčková Ph.D. demonstrates how tricky and arduous HAE diagnosis can be. The course of HAE is highly variable, even within a single family. Therefore, it is crucial to involve all physicians in the early identification of potential HAE patients. Only in this way can we influence the morbidity and mortality associated with this disease.
The section dedicated to hereditary angioedema on the proLékaře.cz portal allows for the dissemination of information about this disease amongst a wide professional audience, who may encounter it in the context of differential diagnosis or patient care. Therefore, I support the HAE section and recommend your attention.
MUDr. Roman Hakl, Ph.D.
Institute of Clinical Immunology and Allergology, Faculty of Medicine, Masaryk University and St. Anne's University Hospital in Brno.
References:
1. Maurer M., Magerl M. et al. The international WAO/EAACI guideline for the management of hereditary angioedema – the 2017 revision and update. Allergy 2018; 73 (8): 1575–1596, doi: 10.1111/all.13384.
2. Hakl R., Kuklínek P., Kadlecová P., Litzman J. Hereditary angiooedema with C1 inhibitor deficiency: characteristics and diagnostic delay of Czech patients from one centre. Allergol Immunopathol (Madr) 2016; 44 (3): 241–245, doi: 10.1016/j.aller.2015.09.003.
3. Magerl M., Germenis A. E., Maas C., Maurer M. Hereditary angioedema with normal C1 inhibitor: update on evaluation and treatment. Immunol Allergy Clin North Am 2017; 37 (3): 571–584, doi: 10.1016/j.iac.2017.04.004.
4. Bork K., Wulff K., Witzke G., Hardt J. Hereditary angioedema with normal C1-INH with versus without specific F12 gene mutations. Allergy 2015; 70 (8): 1004–1012, doi: 10.1111/all.12648.
5. Bork K., Wulff K., Steinmüller-Magin L. et al. Hereditary angioedema with a mutation in the plasminogen gene. Allergy 2018; 73 (2): 442–450, doi: 10.1111/all.13270.
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