Congenital long QT syndrome is electrocardiographically characterized by a prolonged QT interval and polymorphic ventricular arrhythmias (torsade de pointes). These cardiac arrhythmias may result in recurrent syncope, seizure, or sudden death (Jongbloed et al., 1999).
A form of torsade de pointes in which the first beat has a short coupling interval has been described (613600).
Genetic Heterogeneity of Long QT Syndrome
Other forms of LQT syndrome (LQTS) are LQT2 (613688), caused by mutation in the KCNH2 gene (152427); LQT3 (603830), caused by mutation in the SCN5A gene (600163); LQT4 (see 600919), caused by mutation in the ANK2 gene (106410); LQT5 (613695), caused by mutation in the KCNE1 gene (176261); LQT6 (613693), caused by mutation in the KCNE2 gene (603796); LQT7 (Andersen cardiodysrhythmic periodic paralysis, 170390), caused by mutation in the KCNJ2 gene (600681); LQT8 (618447), caused by mutation in the CACNA1C gene (114205); LQT9 (611818), caused by mutation in the CAV3 gene (601253); LQT10 (611819), caused by mutation in the SCN4B gene (608256); LQT11 (611820), caused by mutation in the AKAP9 gene (604001); LQT12 (612955), caused by mutation in the SNTA1 gene (601017); LQT13 (613485), caused by mutation in the KCNJ5 gene (600734); LQT14 (616247), caused by mutation in the CALM1 gene (114180), LQT15 (616249), caused by mutation in the CALM2 gene (114182); and LQT16 (618782), caused by mutation in the CALM3 gene (114183).
Approximately 10% of LQTS patients in whom a mutation is identified in one ion channel gene carry a second mutation in the same gene or in another ion channel gene (Tester et al., 2005).
Reviews
Giudicessi and Ackerman (2016) reviewed the role of Ca(2+) cycling in cardiac repolarization and in the pathogenesis of long QT-associated cardiac arrhythmias. [from OMIM]
