CACNA1D and major depressive disorder: In the brain, voltage-gated calcium channel subunit alpha 1C (CACNA1C), Cav1.2, and CACNA1D, Cav1.3 (common variants in CACNA1C and CACNA1D identified with BD, MDD, or schizophrenia), are the predominant L-type Cav channels and are expressed in various cell types including NPC.