Long QT syndrome: Cellular basis and arrhythmia mechanism in LQT2

LQT2 is one form of the congenital long QT syndrome. It results from mutati ons in the human ether-a-go-go-related gene (HERG), and more than 80 mutati ons, usually causing single amino acid substitutions in the HERG protein, a re known, HERG encodes the ion channel pore-forming subunit protein for the rapidly activating delayed rectifier K+ channel (I-Kr) in the heart. This review summarizes current findings about mutations causing LQT2, the mechan isms by which mutations may cause the clinical phenotype of a reduction in I-Kr and a prolonged QT interval, and how this may be involved in the gener ation of ventricular arrhythmias.