Expansion of CAG repeats within the ATXN1 gene encoded the cytosol/nuclear protein ataxin-1 (Atxn1) causes the adult-onset neurodegenerative disease SCA1 characterized by progressive ataxia, oculomotor deficits, pyramidal/extrapyramidal signs [207,208,209,210,211]. The gene discussed is ATXN1; the disease is Progressive cerebellar ataxia.