Other CACNA1C mutations also caused QT prolongation and cardiac arrhythmias (Gillis et al., 2012; Boczek et al., 2013, 2015b; Fukuyama et al., 2013, 2014; Hennessey et al., 2014; Wemhöner et al., 2015; Landstrom et al., 2016; Sutphin et al., 2016), but their cellular mechanisms underlying cardiac arrhythmias remain relatively unexplored, and the causal link between the CACNA1C mutations and ventricular arrhythmias is not addressed directly. Here, CACNA1C is linked to cardiac rhythm disease.