The progressive retinal and neurodegenerative disease Spinocerebellar Ataxia type 7 (SCA7) is caused by CAG trinucleotide repeat expansion of the ATXN7 gene, resulting in polyglutamine (polyQ) expansion at the amino terminus of the Atxn7 protein (Giunti et al., 1999; David et al., 1997). The gene discussed is ATXN7; the disease is spinocerebellar ataxia 7.