CACNA1C and familial long QT syndrome: Timothy syndrome (TS), which manifests as severe LQTS and multiorgan dysfunction, is mainly caused by gain-of-function mutations located in CACNA1C alternative splicing exon 8 which leads to almost complete loss of voltage-related channel inactivation, resulting in maintained inward Ca2+ current, and prolonged Ca2+ current that delay cardiomyocyte repolarization (104–106).