INTRODUCTIONLong QT syndrome (LQTS), an inherited cardiac arrhythmia, is a disorder of ventricular repolarisation characterised by electrocardiographic abnormalities and the onset of torsades de pointes leading to syncope and sudden death. Genetic polymorphisms in 5 well-characterised cardiac ion channel genes have been identified to be responsible for the disorder. The aim of this study is to identify disease-causing mutations in these candidate genes in a LQTS family.

MATERIALS AND METHODSThe present study systematically screens the coding region of the LQTS-associated genes (KCNQ1, HERG, KCNE1, KCNE2 and SCN5A) for mutations using DNA sequencing analysis.

RESULTSThe mutational analysis revealed 7 synonymous and 2 non-synonymous polymorphisms in the 5 ion channel genes screened.

CONCLUSIONWe did not identify any clear identifiable genetic marker causative of LQTS, suggesting the existence of LQTS-associated genes awaiting discovery.

Adolescent ; Adult ; Child ; DNA Mutational Analysis ; ERG1 Potassium Channel ; Ether-A-Go-Go Potassium Channels ; analysis ; genetics ; Female ; Frameshift Mutation ; Humans ; KCNQ1 Potassium Channel ; analysis ; genetics ; Long QT Syndrome ; genetics ; Male ; Middle Aged ; Muscle Proteins ; analysis ; genetics ; NAV1.5 Voltage-Gated Sodium Channel ; Polymorphism, Genetic ; genetics ; Potassium Channels, Voltage-Gated ; analysis ; genetics ; Sodium Channels ; analysis ; genetics ; Trans-Activators