ATXN3 and Parkinson disease: We examined gait in well-established fly models of SCA3 and PD, in which a mutant form of ATXN3 with 84 expanded polyglutamine repeats [mutATXN3-(CAG)84] and alpha-synuclein (Chouhan et al., 2016; Feany and Bender, 2000), respectively, were expressed, both of which have no apparent homologue in the fly.