Cerebellartissue from SCA7 patients exhibits extensive loss of cerebellar Purkinjecells.123,124 As with other polyQ diseases, nuclear inclusionsare common in vulnerable populations.125,126 SCA7 is causedby a CAG repeat expansion at the 5′ end of the coding regionof the ataxin-7 gene.127,128 While healthy individuals possessalleles ranging in size from 7 to 35 CAGs, diseased expanded SCA7CAG repeats are among the most unstable of all coding repeat expansions,with patients having 37 to >300 repeats.128. The gene discussed is ATXN7; the disease is spinocerebellar ataxia 7.