No significant pre‐post differences in gait or balance outcomes because of the fatiguing task. Fatigue did not worsen gait characteristics or balance scores in PD in either medication state. Also, no interaction with medication (ON vs. OFF)—being on levodopa did not change fatigue’s effect. BDNF genotype had no effect on fatigue response. Concludes an acute fatiguing bout did not impair gait/balance in this PD sample. This evidence concerns the gene BDNF and Parkinson disease.