Hereditary angioedema in the Baltic states

Background. Hereditary angioedema (HAE) is a rare and life-threatening inborn error of the immunity, characterized by recurrent episodes of subcutaneous or submucosal edema. It’s estimated prevalence ranges from 1 in 10,000 to 1 in 50,000 inhabitants worldwide. HAE is mainly caused by deficient or dysfunctional C1-INH, leading to overproduction of bradykinin.
Objective. To describe a prevalence and clinical diversity of HAE in the Baltic states – Latvia, Lithuania and Estonia.
Methods. In this restrospective study clinical and laboratory data of 67 HAE patients (WAO/EAACI,2017) from Latvia, Lithuania and Estonia were analyzed.
Results. Between 2004 and 2020 HAE was diagnosed in 12 patients (11 women and 1 man) from Latvia (total population 1,9 mln), 31 patients (16 women, 14 men, 1 child) from Lithuania (total population 2,8 mln) and 24 patients (11 women, 10 men, 3 children) from Estonia (total population 1,3 mln). Almost all patients (66/67) were diagnosed with C1-INH associated HAE (either I/II type). The diagnosis was most commonly made in adults between the ages of 31 and 70 years. There were recorded 2 fatal outcomes due to HAE attack (in Lithuania). Genetic analysis of the SERPING1 gene was performed in 7 Latvian patients (pathogenic variants detected in 3 cases), 5 Lithuanian patients (pathogenic variants in 2 cases) and in 6 Estonian patients (pathogenic variants in 5 cases). Majority of the patients (32/43) had uncontrolled severe angioedema attacks, including abdominal and airway edema on average 2-4 times per month. The median time between onset of HAE symptoms and diagnosis – 10 years.
Conclusions. According to the epidemiological data, it is expected that over 100 HAE patients in each Baltic country should be diagnosed. Current data shows clear underdiagnosis of HAE. We suggest, that the reason is a lack of awareness of HAE among physicians, the intermittent nature of the symptoms and non-specific signs of the disorder, that contribute to underdiagnosis, a significant delay in proper diagnosis and thus undertreatment. Timely HAE diagnosis and specific treatment can eliminate life-threatining attacks of this disease and increase quality of life significantly.