Moreover, previous studies have shown neuronal loss in the substantia nigra pars compacta, which was associated with decreased dopamine transporter binding in the putamen and caudate in SCA3 patients (Rub et al., 2008; Braga-Neto et al., 2012b; Yen et al., 2002). This evidence concerns the gene SLC6A3 and Spinocerebellar ataxia type 3.