CACNA1A and episodic ataxia type 2: Moreover, gender differences were described in various CACNA1A gene mutations, e.g., SCA 6 as an example of trinucleotides extension, episodic ataxia type 2 (EA2) in case of loss-of-function, and familial hemiplegic migraine-1 (FHM1) an example of gain-of-function missense mutation.