KCND3 and cerebellar ataxia: Very recently, an involvement of Kv4.3 subunits in epilepsy was also suggested by the identification of a de novo mutation (p.Arg293_Phe295dup) in the relevant KCND3 gene causing a severe channel dysfunction in a patient with complex early onset cerebellar ataxia, intellectual disability, oral apraxia and epilepsy.