In addition to SCA6, mutations in CACNA1A are associated with at least two dominantly inherited disorders, episodic ataxia type 2 and familial hemiplegic migraine, both of which clinically overlap with SCA6 (Ophoff et al., 1996; Todi et al., 2007; Du and Gomez, 2018). The gene discussed is CACNA1A; the disease is familial hemiplegic migraine.