CACNA1A and episodic ataxia type 2: 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).