ataxia type 2hereditary spinocerebellar ataxiaspinocerebellar ataxia friedreichspinocerebellar ataxia diagnosisprogressive spinocerebellar ataxiaspinocerebellar ataxia prognosisspinocerebellar ataxia 2ataxia typescerebellar ataxia type 2spinocerebellar ataxia cureinfantile onset spinocerebellar ataxiasca spinocerebellar ataxia