Genetic background predisposing the drug-induced long QT syndrome

Molecular and cellular mechanisms underlying the QT prolongation have been elucidated largely because of the recent understanding of the generation of the congenital forms of QT prolongation; i.e., the long QT syndrome. To date, at least 7 different genes that modulate cardiac ion channels were identitied to be associated with the syndrome. In the clinical setting, the drug-induced long QT syndrome is more frequently seen and therefore important. We found several mutations as well as an SNP specific among the Japanese population in probands referred to as the secondary long QT patients, including the drug-induced cases. These findings raised the potential that there are also predisposing risk factors at patient's side.