Table 3.
Classification of genetic evidence for genes reported to be associated with LQTS based on the work of a multicentered, international clinical domain channelopathy working group [1, 4].
| Gene | LQTS | Acquired LQTS | Multiorgan subtype | Frequency |
|---|---|---|---|---|
| CACNA1C | Moderate | Definitive (Timothy syndrome) | ~1–2% [29] | |
| CALM1 | Definitivea | ~1–2% [30] | ||
| CALM2 | Definitivea | ~1% [30] | ||
| CALM3 | Definitivea | <1% [31] | ||
| KCNE1 | Limited | Strong | <1% [32] | |
| KCNH2 | Definitive | ~25–30% [33] | ||
| KCNJ2 | Limited | Definitive (Andersen-Tawil syndrome) | <1% [34] | |
| KCNQ1 | Definitive | ~30–35% [35] | ||
| SCN5A | Definitive | ~5–10% [36] | ||
| TRDN | Strongb | ~2% [37] |
aIf presenting in infancy or early childhood with heart block and severe QT prolongation.
bPresenting with negative T waves in precordial leads, and exercise-induced arrhythmias in early childhood related to homozygous or compound heterozygous frameshift mutations.