Table 1:

ClinGen reappraisal of genes associated with inherited arrhythmia syndromes

ClinGen Class	Long QT syndrome	Brugada syndrome	Catecholaminergic polymorphic VT	Short QT syndrome	Other
Definitive	KCNQ1, KCNH2, SCN5A, CALM1/2/3	SCN5A	RYR2, CASQ2(AR), TRDN, TECRL	KCNH2	CACNA1C (Timothy), KCNJ2 (Anderson-Tawil)
Strong	TRDN (AR)	—	—	KCNQ1, SLC4A3 *	KCNE1 (aLQTS), KCNE2 (aLQTS)
Moderate	CACNA1C	—	CASQ2(AD), CALM1/2/3	SLC4A3*, KCNJ2	—
Limited	CAV3, KCNE1, KCNJ2	—	—	—	—
Disputed/ No evidence	SNTA1, AKAP9, ANK2, KCNE2, KCNJ5, SCN4B	20 genes	ANK2, KCNJ2, PKP2, SCN5A	CACNA1C, CACNA2D1, CACNB2, SCN5A, SLC22A5 **	—

Adapted from ClinGen reappraisals of LQTS [4], BrS [5], and CPVT/SQTS [6].

^*The panel reviewing SLC4A3 was divided whether to classify it as having strong or moderate evidence.

^**This gene causes primary systemic carnitine deficiency which may mimic SQTS. Abbreviations: VT=ventricular tachycardia, AR=autosomal recessive, AD=autosomal dominant, aLQTS=acquired long QT syndrome. Timothy Syndrome and Anderson-Tawil Syndrome are characterized by long QT syndrome in conjunction with characteristic non-cardiac phenotypes. CALM1, CALM2, and CALM3 are 3 distinct genes that all encode an identical calmodulin protein.