Gene1-150 | Current | Frequency | ECG | Circumstances surrounding events | DQT with exercise | |
LQT1 | KvLQT1 | ↓IKs | 40% | Broad T | Exercise, emotion | – |
LQT2 | HERG | ↓IKr | 40% | Bifid T | Sudden auditory stimuli | Normal |
LQT3 | SCN5A | ↑INa | 10% | Long isoelectric ST | Sleep | Supernormal |
LQT4 | Unknown | Rare | ||||
LQT5 | minK | ↓IKs | Rare | |||
LQT6 | MiRP1 | ↓IKr(?) | Rare | |||
JLN1 | KvLQT1 | ↓IKs | Rare | Marked ↑QT | Exertion | |
JLN2 | minK | ↓IKs | Rare | Marked ↑QT | Exertion |
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”.