PPP2R2B and autosomal dominant cerebellar ataxia: The frequency of different SCA types in our sample cohort is SCA12 (8.6%), SCA2 (8.4%), SCA1 (4.8%), SCA3 (2%), SCA7 (0.5%), SCA6 (0.1%), and SCA17 (0.1%) while 73.2% remain genetically uncharacterized for screened loci (Figure1A).