Mutations in the CACNA1A gene, encoding for the P/Q-type voltage-gated calcium channel (Cav2.1), are known to result in neurological disorders, such as episodic ataxia type 2 (EA2), familial hemiplegic migraine type 1 (FHM1) and progressive spinal cerebellar ataxia type 6 (SCA6) (Ophoff et al., 1996; Zhuchenko et al., 1997). Here, CACNA1A is linked to familial or sporadic hemiplegic migraine.