Table 1.

Long QT syndrome genotypes

LQT type	Gene	Function and abnormality
LQT1	KCNQ1	IKs* ↓
LQT2	KCNH2	IKr† ↓
LQT3	SCN5A	INa‡ ↑
LQT4	ANKB	INa,K ↓ INCX§ ↓
LQT5	KCNE1	IKs ↓
LQT6	KCNE2	IKr ↓
LQT7	KCNJ2	IK1 ↓
LQT8	CACNA1C	ICa-L‖ ↑
LQT9	CAV3	INa ↑
LQT10	SCN4B	INa ↑

^*I_Ks -Slow component of delayed rectifier current

^†I_Kr -Rapid component of delayed rectifier current

^‡I_Na -Inward sodium current

^§I_NCX: Na⁺/Ca⁺ exchange current

^‖I_Ca-L: L type Ca⁺ current