title: Mutation site dependent variability of cardiac events in Japanese LQT2 form of congenital long-QT syndrome.
abstract: BACKGROUND
  In the LQT2 form of long QT syndrome (LQTS), mutation sites are reported to correlate with clinical phenotypes in Caucasians, but the relationship in Asian patients remains unknown. The present study was designed to determine whether the location of KCNH2 mutations would influence the arrhythmic risk in LQT2 patients.
  
  
  RESULTS
  In 118 genetically-confirmed LQT2 patients (69 families, 62 KCNH2 mutations), the ECG parameters, Schwartz scores, and the incidence of cardiac events, defined as syncope, aborted cardiac arrest, and sudden cardiac death, were evaluated. To examine the effect of mutation sites, the participants were divided accordingly: pore (n=56) and non-pore (n=62) groups. The corrected QTend interval was significantly greater in the pore than in the non-pore group (QTc; 522+/-63 ms vs 490+/-49 ms, p=0.002). In this study, the clinical course of each of the probands did not differ according to the mutation sites, whereas non-probands carrying the pore site mutation experienced their first cardiac events at significantly younger age than those with the non-pore site mutation (log-rank, p=0.0005).
  
  
  CONCLUSIONS
  In a Japanese LQT2 cohort, family members with the pore site mutation were at higher arrhythmic risk than those with the non-pore site mutation.
authors.affiliation: Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan.
authors.forename: Iori
authors.initials: I
authors.lastname: Nagaoka
authors.forename: Wataru
authors.initials: W
authors.lastname: Shimizu
authors.forename: Hideki
authors.initials: H
authors.lastname: Itoh
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Tomoko
authors.initials: T
authors.lastname: Sakaguchi
authors.forename: Yuko
authors.initials: Y
authors.lastname: Oka
authors.forename: Keiko
authors.initials: K
authors.lastname: Tsuji
authors.forename: Takashi
authors.initials: T
authors.lastname: Ashihara
authors.forename: Makoto
authors.initials: M
authors.lastname: Ito
authors.forename: Hidetada
authors.initials: H
authors.lastname: Yoshida
authors.forename: Seiko
authors.initials: S
authors.lastname: Ohno
authors.forename: Takeru
authors.initials: T
authors.lastname: Makiyama
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Noda
authors.forename: Shiro
authors.initials: S
authors.lastname: Kamakura
authors.forename: Masaharu
authors.initials: M
authors.lastname: Akao
authors.forename: Minoru
authors.initials: M
authors.lastname: Horie
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D044466:Asian People / Q000235:genetics* / Q000706:statistics & numerical data*; D002648:Child; D002675:Child, Preschool; D018389:Codon, Nonsense; D015331:Cohort Studies; D018572:Disease-Free Survival; D005192:Family Health; D005260:Female; D017353:Gene Deletion; D014644:Genetic Variation; D006801:Humans; D008133:Long QT Syndrome / Q000208:ethnology* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D012307:Risk Factors; D016171:Torsades de Pointes / Q000208:ethnology / Q000235:genetics
chemical_list: D018389:Codon, Nonsense