title: [Novel mutations of potassium channel KCNQ1 S145L and KCNH2 Y475C genes in Chinese pedigrees of long QT syndrome].
abstract: OBJECTIVE
  Hereditary long QT syndrome (LQTS) is a cardiac disorder characterized by prolongation of QT interval on electrocardiograms (ECGs) and syncope and sudden death caused by a specific multi-polymorphic ventricular tachyarrhythmia known as torsade de pointes. LQTS is caused by mutations in cardiac sodium channel gene SCN5A; potassium channel subunit genes KCNQ1, KCNH2, KCNE1, KCNE2, KCNJ2; calcium channel gene Cav2.1. and ankyrin-B gene ANK2.
  
  
  METHODS
  We characterized 77 Chinese LQTS patients with clinical manifestations and mutations in the main LQTS genes, KCNQ1 and KCNH2 using PCR and sequence analysis.
  
  
  RESULTS
  The spectrum of ST-T-wave patterns of 24 (31.2%) probands were considered as LQT1, 42 (54.5%) as LQT2 and 3 (3.9%) as LQT3. The remaining 8 (10.3%) could not be characterized. The average age for this population of LQTS patients was (27.6 +/- 16.4) years and the average QTc (561 +/- 70) ms, and the age of the first syncopal attack was (17.6 +/- 14.7) years. The triggering factors for cardiac events happening in these mutation carriers included physical exercise, emotional excitement and auditory irritation. We identified 4 KCNQ1 mutations and 7 KCNH2 mutations. Six of them were first identified with some data already shown. In this paper we showed the data of 6 other mutations.
  
  
  CONCLUSIONS
  LQT2 is the most common type of LQTS in Chinese; 2 mutations of KCNQ1 and KCNH2 were first identified in this report; there are some differences between Chinese and North American or European LQTS patients in clinical characters and ECG.
authors.affiliation: Cardiology Division, People's Hospital, Peking University, Beijing 100044, China.
authors.forename: Wen-ling
authors.initials: WL
authors.lastname: Liu
authors.forename: Da-yi
authors.initials: DY
authors.lastname: Hu
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Cui-lan
authors.initials: CL
authors.lastname: Li
authors.forename: Xu-guang
authors.initials: XG
authors.lastname: Qin
authors.forename: Yun-tian
authors.initials: YT
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Zhi-ming
authors.initials: ZM
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Dong
authors.forename: Yu
authors.initials: Y
authors.lastname: Qi
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002681:China; D000072237:ERG1 Potassium Channel; D004562:Electrocardiography; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics*; D005260:Female; D006801:Humans; D051657:KCNQ1 Potassium Channel / Q000235:genetics*; D008133:Long QT Syndrome / Q000235:genetics*; D008297:Male; D009154:Mutation; D010375:Pedigree; D018807:Polymorphism, Single-Stranded Conformational
chemical_list: D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human