SCN5A and familial long QT syndrome: Although mutations in CaV1.2 can lead to LQTS, most cases of LQTS can be attributed to mutations in genes encoding the voltage-gated K+ channels KV7.1 (KCNQ1) and KV11.1 (KCNH2), as well as the voltage-gated Na+ channel NaV1.5 (SCN5A) (Modell and Lehmann, 2006).