This dominance may explain the prevalence of channelopathies associated with CaV2.1 (P/Q-type) such as familial hemiplegic migraine type 1, episodic ataxia type 2, and spinocerebellar ataxia type 6 (Pietrobon, 2010). This evidence concerns the gene CACNA1A and familial or sporadic hemiplegic migraine.