To this end, the objectives of this study were to: i) assess intestinal permeability in subjects with newly diagnosed, untreated PD and compare the results to controls without a history of neurological disease or PD; ii) determine whether increased intestinal permeability (“leaky gut”) in PD subjects correlated with markers of bacterial translocation and endotoxin exposure either locally or systemically, and iii) determine whether gut leakiness is associated with mucosal oxidative stress and intestinal neuronal α-synuclein aggregates. The gene discussed is SNCA; the disease is Parkinson disease.