Screening for type II hereditary angioedema—the “poor man’s c1-inhibitor function”
Ankur Kumar Jindal, Valerie Chiang, Prabal Barman, Archan Sil, Sanchi Chawla, Elaine Y. L. Au, Amit Rawat, Philip H. Li
Abstract
Background: Hereditary angioedema (HAE) is a rare genetic disease. Patients with type II HAE have normal or elevated C1-inhibitor (C1-INH) levels but C1-INH protein is dysfunctional. C1-INH function requires careful sample handling and technical expertise and may account for the lack of diagnosed patients with type II HAE in resource-limited countries. Objective: We sought to assess the diagnostic performance of elevated C1-INH levels in diagnosing type II HAE. Methods: gene mutations. Their C1-INH levels were compared with those of matched controls. Results: < .001). Positive and negative predictive values of both a low C4 and an elevated C1-INH level for patients with type II HAE were 100% and 82.9%, respectively. Conclusions: Low C4 and elevated C1-INH levels may be considered as a screening tool for type II HAE, especially in countries where C1-INH function testing is not readily available.