In agreement with the main hypothesis of the present study, Western blot analyses indicated the presence of a hypoxic environment in the substantia nigra of MSA patients compared with PD patients and controls, characterized by the significant accumulation of the hypoxia marker HIF2α (MSA vs C, P = 0.0003; MSA vs PD, P = 0.0084; Fig. 1B,C and Table 1). Here, EPAS1 is linked to Parkinson disease.