spinocerebellar ataxia treatmentspinocerebellar ataxia friedreichspinocerebellar ataxia diagnosisprogressive spinocerebellar ataxiaspinocerebellar ataxia prognosisspinocerebellar ataxia type 4ataxia typesinherited cerebellar ataxiaspinocerebellar ataxia cureinfantile onset spinocerebellar ataxiahereditary cerebellar degenerationsca spinocerebellar ataxia