Genetics of Adult and Fetal Forms of Long QT Syndrome

Long QT syndrome (LQTS) is an inherited cardiac disease characterized by prolongation of QT interval at surface ECG, T-wave abnormalities, and high risk of life-threatening arrhythmias in otherwise healthy young individuals. Currently the LQTS diagnosis is genetically confirmed in nearly 75–85% of LQTS patients, revealing a good knowledge of the genetic bases of the disease. The main LQTS genes are KCNQ1, KCNH2, and SCN5A encoding potassium and sodium cardiac ion channels responsible of the cardiac action potential duration. Minor contributors of LQTS genetic background include genes encoding other cardiac ion channels, ancillary subunits, and protein components forming channels’ macromolecular complexes.