The differences between groups remained significant after performing univariate analysis including age as a covariate (MSA vs C, P = 0.021; MSA vs PD, P = 0.05) and confirmed that changes in HIF2α levels were determined by diagnosis (P = 0.022) but not age (P = 0.496) or sex (P = 0.502), discarding a possible confounding effect. The gene discussed is EPAS1; the disease is Parkinson disease.