The human CACNA1A gene encodes the pore-forming subunit of Cav2.1, the voltage-gated P/Q-type calcium channel. Inclusion of auxiliary subunits modulate gating and pharmacological characteristics, while the inwardly rectifying potassium channel allows the membrane potential to be altered with changes in extracellular K+. Mutations in CACNA1A are responsible for several inherited neurologic disorders including, familial hemiplegic migraine, episodic ataxia type2, and spinocerebellar ataxia type 6 epilepsy. Cav2.1 channels expressed in neurons are therapeutic targets in pain.