Clinical characteristics of 5 chinese LQTS families and phenotype-genotype correlation

  • Lian Jiangfang
  • Cui Changcong
  • Xue Xiaolin
  • Huang Chen
  • Cui Hanbin
Article

DOI: 10.1007/BF02831990

Cite this article as:
Jiangfang, L., Changcong, C., Xiaolin, X. et al. J. Huazhong Univ. Sci. Technol. [Med. Sci.] (2004) 24: 208. doi:10.1007/BF02831990

Summary

In order to assess the clinical manifestations and electrocardiogram (ECG) characteristics of Chinese long QT syndrome (LQTS) patients and describe the phenotype-genotype correlation, the subjects from 5 congenital LQTS families underwent clinical detailed examination including resting body surface ECG. QT interval and transmural dispersion of repolarization (TDR) were manually measured. Five families were genotyped by linkage analysis (polymerase chain reacting-short tandem repeat, PCR-STR). The phenotype-genotype correlation was analyzed. Four families were LQT2, 1 family was LQT3. Twenty-eight gene carriers were (14 males and 14 females) identified from 5 families. The mean QTc and TDRc were 0.56±0.04 s (range 0.42 to 0.63) and 0.16±0. 04 s (range 0.09 to 0.24) respectively. 35.7% (10/28) had normal to borderline QTc (≦0.460 s). There was significant difference in QTc and TDRc between the patients with symptomatic LQTS and those with asymptomatic LQTS, and there was significant difference in TDRc between the asymptomatic patients and normal people also. A history of cardiac events was present in 50% (14/28), including 9 with syncope, 2 with sudden death (SD) and occurred in the absence of β-blocker. Three SDs occurred prior to the diagnosis of LQTS and had no ECG record. Two out of 5 SDs (40%) occurred as the first symptom. Typical LQT2 T wave pattern were found in 40% (6/15) of all affected members. The appearing-normal T wave was found in one LQT3 family. Low penetrance of QTc and symptoms resulted in diagnostic challenge. ECG patterns and repolarization parameters may be used to predict the genotype in most families. Genetic test is very important for identification of gene carriers.

Key words

long QT syndrome clinical characteristics phenotype-genotype correlation 

Copyright information

© Springer 2004

Authors and Affiliations

  • Lian Jiangfang
    • 1
  • Cui Changcong
    • 1
  • Xue Xiaolin
    • 1
  • Huang Chen
    • 2
  • Cui Hanbin
    • 1
  1. 1.Department of CardiologyThe First Hospital of Xian Jiaotong UniversityXianChina
  2. 2.Central Laboratory for Biomedical ResearchMedical School of Xian Jiaotong UniversityXianChina

Personalised recommendations