tokens: Autosomal dominant cerebellar ataxia type I is composed mainly of 3 prevalent spinocerebellar ataxia types with different pathogenic loci , specifically spinocerebellar ataxia 1 ( 6p24 - p23 ) , spinocerebellar ataxia 2 ( 12q24.1 ) , and spinocerebellar ataxia 3 ( 14q32.1 ) .