Hereditary angioedema in Japan: genetic analysis of 13 unrelated cases.

INTRODUCTION: The molecular bases and clinical features of hereditary angioedema (HAE) have not been systematically documented in Japan or in other Asian countries. Thus, the authors researched the genetic and clinical characteristics of Japanese patients with HAE. METHODS: The authors analyzed the CIINH gene for mutations in 13 unrelated Japanese patients with HAE by means of the polymerase chain reaction and nucleotide sequencing. In addition, the authors searched the literature from January 1969 to October 2010 on Japanese patients with HAE. RESULTS: Seven of the mutations found were novel, including 4 missense mutations (8728T>G, 8831C>A, 16661T>G and 16885C>A), 2 frameshift mutations (2281_2350del70, 14158delT) and 1 large deletion (at least 1 kb-length deletion including exon 4), whereas 6 mutations had previously been reported in European populations. CONCLUSIONS: The genetic and clinical characteristics in Japanese patients with HAE may be similar to those in Western patients although our sample size is small and the authors identified 7 novel mutations.