Session 1: Recurrent angioedema: Causes and differential diagnosis

The first session began with a diagnosis. Professor Laurence Bouillet from Grenoble Alpes University Hospital in France walked through the current best practices in the diagnosis of isolated and recurrent/chronic angioedema. She suggested, in conclusion, that the diagnostic workflow outlined in a recent paper on diagnosing HAE with normal C1 inhibitor provides a strong process to follow for all undiagnosed patients with recurrent angioedema.

Her concluding remarks were that diagnosis requires a methodical and comprehensive approach that integrates clinical features, trigger factors, drug exposure, family history, and, when necessary, genetic testing.

Dr Mar Guilarte facilitated a roundtable discussion on approaches to recurrent angioedema and daily practice in diagnosis. The panel included: Prof Anete Grumach (Brazil), Dr Ankur Jindal (India), Prof Philip Li (Hong Kong), Dr Stephen Betschel (Canada), Prof Petra Staubach-Renz (Germany).

In this session, three data presentations were given by clinicians and scientists:

Investigation of early complement parameters and C1INH values in newborns with a positive family history of HAE-C1INH

The recipient of the Young Researcher Award, Dr Lili Voloncs-Mindszenthy, presented work aimed at addressing the problem of diagnosing HAE in newborns. The data demonstrated that while the complement system is immature at birth, the functional activity of C1 inhibitor best differentiates between babies with HAE due to C1 inhibitor deficiency and healthy newborns, and could be a reliable early signal of HAE at birth.

Suspicion of hereditary angioedema with normal C1 inhibitor – Insights into clinical characteristics and outcomes of genetic testing from the first global ACARE project

This research was presented by Dr Katrin Schön from Charité – Universitätsmedizin, Germany. The research group’s work was to increase worldwide access to genetic testing for previously unknown types of HAE with normal C1 inhibitor levels and to better understand the genetic causes of the disease. In conclusion, the researchers believed that their data showed that the number of people found to have a known HAE with normal C1 Inhibitor gene mutation was low, and that a patient’s signs and symptoms of the disease do not indicate the probability of a positive genetic finding.

Inheritance patterns of hereditary angioedema due to C1 inhibitor deficiency in 72 families

Dr Hanga Réka Horváth, from Semmelweis University in Hungary, gave the final presentation in this session. The work she presented examined patterns in a cohort of 72 families with HAE. They felt able to conclude that the kinin-kallikrein system plays an important role during pregnancy, which might lead to selection bias in carriers/non-carriers of pathogenic variants in the SERPING1 gene.