Table 1

Congenital long QT syndromes

Gene1-150 Current Frequency ECG Circumstances surrounding events DQT with exercise
LQT1 KvLQT1 ↓IKs 40%Broad TExercise, emotion
LQT2 HERG ↓IKr 40%Bifid TSudden auditory stimuliNormal
LQT3 SCN5A ↑INa 10%Long isoelectric STSleepSupernormal
LQT5 minK ↓IKs Rare
LQT6 MiRP1 ↓IKr(?)Rare
JLN1 KvLQT1 ↓IKs RareMarked ↑QTExertion
JLN2 minK ↓IKs RareMarked ↑QTExertion
  • LQT1-6 are autosomal dominant without deafness (also termed Romano-Ward syndrome). JLN: Jervell-Lange-Neilsen syndrome (autosomal recessive with deafness) arises in individuals who inherit abnormal alleles from both parents, and is much rarer.

  • 1-150 Some of these genes have alternate names. The “official” terms forKvLQT1, HERG,minK, and MiRP1are KCNQ1, KCNH2,KCNE1, and KCNE2, respectively. MinK is also known asIsK. HERG is an acronym for “Human Ether a-go-go-Related Gene”, andMiRP1 is an acronym for “MinK-Related Protein -1”.