FGD4 and Parkinson disease: qPCR analysis confirmed that <i>FGD4</i> and <i>MAN2B1</i> expression levels were significantly higher in patients with PD compared to healthy controls (<i>p</i> < 0.05).<h4>Conclusion</h4><i>FGD4</i> and <i>MAN2B1</i> act as lysosomal biomarkers associated with PD and exhibit strong correlations with genes involved in PD-related freezing of gait.