Pediatric Cardiology and Cardiac Surgery
Vol.24 No.2 2008 (109-115)

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Wataru Shimizu

Division of Cardiology, Department of Internal Medicine, National Cardiovascular Center, Osaka, Japan


Congenital long QT syndrome (LQTS) is a hereditary disorder characterized by a prolonged QT interval in the ECG and a polymorphic ventricular tachycardia known as Torsade de Pointes. Genetic studies to date have identified 10 forms of congenital LQTS caused by mutations in genes of ion channels or membrane adapter. Genotype-phenotype correlation in clinical and experimental studies has been investigated in detail in the LQT1, LQT2, and LQT3 syndromes, which constitute more than 90% of genotyped LQTS patients, enabling us to stratify risk and to effectively treat genotyped patients. More recently, mutation-sitespecific differences in clinical phenotype in the LQT1 and LQT2 syndrome have been reported.