SCN8A and Ataxia: Variants in other voltage-gated cation channels such as KV1.2, KV3.3, CaV2.1, and CaV3.1 channels directly or through parallel-fibre/climbing-fibre pathway indirectly decreased Purkinje neuronal function, causing episodic and chronic ataxia.33, 34, 35, 36 Several mouse models carrying SCN8A LOF variants showed ataxia phenotypes and decreased firing rates of Purkinje neurons.15