The first Hereditary Angioedema cohort in Hong Kong

Abstract

Background and Aims: Hereditary angioedema (HAE) was almost unheard of in Hong Kong prior to the establishment of its first public Clinical Immunology service in 2018. Since then, Queen Mary Hospital established a dedicated Immunology Clinic and the first HAE registry in the region. The aim was to study the prevalence as well as the clinical features of these previously undiagnosed HAE patients in Hong Kong. Methods: From 2018-2019, all referrals for angioedema and suspected HAE were screened and reviewed. Referrals were encouraged by conducting a series of educational lectures as well as a dedicated Immunology chapter in the territory-wide handbook accessible to all public-sector doctors. All confirmed HAE patients consented to participate in the Hong Kong HAE registry and their clinical features were reviewed for analysis. Results: Between July 2018 to July 2019, 81 referrals were received for workup of angioedema and/or suspected immunodeficiency. Eight families with HAE were identified. Seven families carried unique mutations for HAE I, and one family carried a mutation for HAE II. After family screening, 19 individuals were confirmed to have HAE, with a further 91 potentially affected family members pending screening. More than 20% of patients had a history of laryngeal attacks, and 64% of patients had been hospitalized (at least once) for acute angioedema attacks. All confirmed HAE patients were offered C1 inhibitor replacement in a structured protocol. Conclusions: We describe the clinical characteristics of the first HAE registry in Hong Kong and our region, which also enabled provision of much needed C1 inhibitor replacement for these patients.