Table 2 Pathogenic gene mutations associated with SQTS variants
From: Sudden cardiac death: focus on the genetics of channelopathies and cardiomyopathies
Mutated gene | Encoded protein | Functional alteration | SQTS variant |
|---|---|---|---|
KCNH2 | α-subunit of the voltage-gated potassium channel that mediates the rapidly activating component of the delayed rectifying potassium current (IKr) | Gain-of-function mutation that leads to an increased potassium current and shortening of the action potential [36, 129] | SQTS1 |
KCNQ1 | α-subunit of the voltage-gated potassium channel that mediates the slow component of the delayed rectifier potassium current (IKs) | Increased repolarizing current [112] | SQTS2 |
KCNJ2 | Inward rectifier potassium channel Kir2.1 (IK1) | Gain-of-function mutation that leads to an increase in the outward IK1 current and acceleration of the final phase of repolarization [130] | SQTS3 |
CACNAC1C | α1-subunit of the L-type calcium channel | Loss-of-function mutation leading to a reduction in the depolarizing current [54] | SQTS4 |
CACNB2 | β2-subunit of the L-type calcium channel | Loss-of-function mutation leading to a reduction in the depolarizing current [54] | SQTS5 |
CACNA2D1 | α-2/δ subunit of the L-type calcium channel | Loss-of-function mutation leading to a reduction in the depolarizing current [131] | SQTS6 |