CAG repeats in the last exon of the longest isoform of CACNA1A cause SCA6, and missense mutations affecting the calcium channel-encoding sequence cause progressive cerebellar ataxia, familial hemiplegic migraine (FHM1), and episodic ataxia type 2 (EA2) [49]. The gene discussed is CACNA1A; the disease is migraine, familial hemiplegic, 1.