Mutations in the CACNA1A gene have been found to be responsible for three disorders with autosomal dominant inheritance: EA2 (MIM: 108500), familial hemiplegic migraine type 1 (FHM1; MIM: 141500), and spinocerebellar ataxia type 6 (SCA6; MIM: 183086). The gene discussed is CACNA1A; the disease is familial or sporadic hemiplegic migraine.