National data shows a significant delay and clear underdiagnosis of hereditary angioedema (HAE) in Latvia, according to a study published in Allergy, Asthma & Clinical Immunology.

To describe the clinical features and genetic spectrum of HAE with C1-inhibitor deficiency in Latvia, the researchers recruited 10 patients diagnosed with HAE types 1 and 2 from 2006 to March 2022.

The researchers performed laboratory testing and genetic testing with Sanger sequencing and whole genome sequencing, followed by clinical data analysis.

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According to the study results, the point prevalence of HAE in Latvia was 0.53 per 100,000 people. There were 9 female patients and 1 male patient, from 8 families. Seven (70%) of them had HAE type 1 and 3 (30%) had HAE type 2. The median age of study participants was 54 years.

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A significant delay in diagnosing the condition was noted in all HAE participants. The median age at which the symptoms started was 15 years, while the diagnosis was established at a median age of 20.5 years. Most notably, 60% of patients had a positive family history of HAE.  

All of the study participants had been hospitalized for HAE 2 times on average in their lifetime. The most prominent symptom was skin (100%), abdominal (80%), and airway (80%) edema. Half of the participants had severe HAE attacks, 10% suffered moderate attacks, and 40% suffered mild attacks.

The HAE diagnosis was molecularly confirmed in 8 patients from 6 families, who had pathogenic variations of serine protease inhibitor gene 1 (SERPING1) discovered. However, 2 patients from 2 families had no pathogenic gene variations found, even after whole genome sequencing.

Read more about HAE diagnosis

“Higher awareness and better information and communication between doctors would improve the diagnosis and management of HAE; as would screening of family members, patients with recurrent angioedema unresponsive to antihistamines and glucocorticoids, and patients with recurrent episodes of severe, unexplained abdominal pain,” Kanepa and colleagues highlighted.

HAE is most often caused by pathogenic variations in the SERPING1 gene, triggering a deficiency or dysfunction of the C1-inhibitor, overproduction of bradykinin, and development of recurrent subcutaneous and submucosal edema. There are 50,000 to 100,000 people suffering from HAE worldwide.


Kanepa A, Nartisa I, Rots D, Gailite L, Farkas H, Kurjane N. National survey on clinical and genetic characteristics of patients with hereditary angioedema in LatviaAllergy Asthma Clin Immunol. Published April 8, 2023. doi:10.1186/s13223-023-00783-6