This group includes SCA1, Machado-Joseph disease (SCA3 or MJD), SCA6, SCA7, SCA17, Huntington's disease, spinal bulbar muscular atrophy (SBMA) and dentatorubral-pallidoluysian atrophy (DRPLA). Here, CACNA1A is linked to dentatorubral-pallidoluysian atrophy.