CACNA1A and ataxia telangiectasia: Among genetically confirmed (or suspected) hereditary ataxias, Friedreich Ataxia (FRDA) (n=178), spinocerebellar ataxias (SCA) (most often SCA2 (n=421), SCA3 (n=268), and SCA6 (n=117)), and ataxia telangiectasia (A-T) (n=85) were most frequently reported (see Fig. 2 for distribution of specific disorders).