Hereditary angioedema-1 and -2 (HAE1 and HAE2) refer to disorders caused by mutation in the SERPING1 (C1HN) gene. The disorders are clinically indistinguishable: both are characterized by episodic local subcutaneous edema and submucosal edema involving the upper respiratory and gastrointestinal tracts. HAE1, representing 85% of patients, is characterized by serum levels of C1NH less than 35% of normal (Cicardi and Agostoni, 1996; Bowen et al., 2001). HAE2 is characterized by normal or even elevated C1NH levels, but the protein is nonfunctional. Genetic Heterogeneity of Hereditary Angioedema See also HAE3 (610618), caused by mutation in the F12 gene (610619) on chromosome 5q35; HAE4 (619360), caused by mutation in the PLG gene (173350) on chromosome 6q26; HAE5 (619361), caused by mutation in the ANGPT1 gene (601667) on chromosome 8q23; HAE6 (619363), caused by mutation in the KNG1 gene (612358) on chromosome 3q27; HAE7 (619366), caused by mutation in the myoferlin gene (MYOF; 604603) on chromosome 10q23; and HAE8 (619367), caused by mutation in the HS3ST6 gene (619210) on chromosome 16p13. See also 300145 for a discussion of angioedema induced by ACE inhibitors. Zuraw (2008), Bork et al. (2020), and Veronez et al. (2021) provided detailed reviews of the clinical features, management, and pathogenesis of the different genetic forms of hereditary angioedema. The pathogenesis is complex and is related to excessive production of bradykinin, which causes dilation, as well as to other signaling pathways that regulate vascular permeability. >> 翻訳 (Google)