Background: Genetic variants in voltage-gated sodium channels (Nav) encoded by SCNXA genes, responsible for INa, and Kv4.3 channels encoded by KCND3, responsible for the transient outward current (Ito), contribute to the manifestation of both Brugada syndrome (BrS) and spinocerebellar ataxia (SCA19/22). This evidence concerns the gene KCND3 and cerebellar ataxia.