CACNA1C and familial long QT syndrome: This will facilitate the efficient generation of multi-subunit channel complexes, such as the L-type calcium channel (CaV1.2, ICa,L) which is crucial for the plateau phase of the cardiac action potential and requires co-expression of CACNA1C, CACNB2B, and CACNA2D1. CaV1.2 GOF variants can cause Timothy Syndrome, a multi-organ dysfunction associated with LQTS (LQTS8) and sudden cardiac death (Splawski et al., 2004).