Mutations in Cav3 disrupt these signaling and coordinating microdomains and can cause structural cardiac and arrhythmic disease such as long QT syndrome (LQT9), sudden infant death syndrome, and hypertrophic cardiomyopathy (Hayashi et al., 2004; Vatta et al., 2006; Cronk et al., 2007). Here, CAV3 is linked to long QT syndrome 9.