Ataxin-3 (AT3) is a 42 kDa intracellular protein that is responsible for the polyglutamine (polyQ) disease spinocerebellar ataxia type 3, when the length of its polyQ tract exceeds about 50 consecutive residues [1]–[3]. This evidence concerns the gene ATXN3 and Spinocerebellar ataxia type 3.