Interestingly, MJD can present with clinical and neuropathological symptoms of Parkinson disease (PD), and this raises the possibility that an interaction between ataxin-3 and a PD-associated protein could be involved in MJD (Gwinn-Hardy et al., 2001; Bettencourt et al., 2011). The gene discussed is ATXN3; the disease is Parkinson disease.