SCN8A and cerebellar ataxia: The identified genes were GNAO1, SCN8A, CACNA1A, SCN1A, WWOX, CDKL5, SCN2A, KCNQ2, STXBP1, and KCNA2. The spectrum of movement disorders include involuntary movements, dystonia, ataxia, chorea, myoclonus, tremors, spasms, and central motor disorders.