For example, panels offered by Transgenomic17 and GeneDx18 test for 13 and 12 LQTS genes, respectively, KCNQ1, KCNH2, andSCN5A (LQT1-3) mutations being most frequent; 3 SQTS genes – mutations in the KCNH2, KCNQ1, andKCNJ2 genes; 4 (Transgenomic) and 2 (GeneDx) CPVT genes, RYR2 mutations being most frequent; and 7 BrS genes, SCN5A mutations being most frequent. Here, KCNQ1 is linked to familial long QT syndrome.