The prevalence of hereditary angioedema in a Chinese cohort with decreased complement 4 levels

Qi Cui; Qingxiu Xu; Yaqi Yang; Wenjing Li; Nan Huang; Hao Chen; Dongxia Ma; Shuchen Zhang; Lin Yang; Rongfei Zhu

doi:10.1016/j.waojou.2021.100620

The prevalence of hereditary angioedema in a Chinese cohort with decreased complement 4 levels

World Allergy Organ J. 2021 Dec 18;15(1):100620. doi: 10.1016/j.waojou.2021.100620. eCollection 2022 Jan.

Authors

Qi Cui¹, Qingxiu Xu¹, Yaqi Yang¹, Wenjing Li¹, Nan Huang¹, Hao Chen¹, Dongxia Ma¹, Shuchen Zhang¹, Lin Yang¹, Rongfei Zhu¹

Affiliation

¹ Department of Allergy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

Abstract

Objective: Hereditary angioedema (HAE) is a rare, life-threatening autosomal dominant disorder. We aimed to investigate the prevalence of HAE in a Chinese population with a decreased Complement 4 (C4) level.

Methods: All the patients present in Tongji Hospital with C4 below lower normal range were included from January 2019 to June 2020. The individual data were extracted from the database and categorized by diagnosis. Patients suspected of HAE were further evaluated by C1 inhibitor level and function test to confirm the HAE diagnosis.

Results: A total of 8226 patients were enrolled in our study, among whom 18 had symptoms similar to HAE and received C1 inhibitor level and function tests. Two (1 male and 1 female) of the 18 patients were identified as HAE patients. This means the prevalence of HAE was 2.43/10 000 among the C4-decreased population and 10.1/10 000 in the C4-decreased population with etiology undetermined. The 2 HAE patients had experienced skin and oropharynx edema attack and received tracheotomy. The female patient had a family history. Laboratory tests showed significant decrease of C4 and C1 inhibitor levels in the 2 patients, both of whom were diagnosed as type 1 HAE.

Conclusion: The prevalence of HAE is low in C4-decreased patients. In a large cohort, C4 level can serve as a practical indicator to screen the HAE patients, but further testing of C1 inhibitor activity and levels is needed to confirm the diagnosis of HAE.

Keywords: Chinese cohort; Complement 4; Etiology; Hereditary angioedema; Prevalence.