Finally, correlation analyses of PMI and HIF2α protein levels in the substantia nigra or visual cortex demonstrated that the presence of hypoxia in MSA brains was independent of the time elapsed between death and the freezing of the sampled tissue (substantia nigra: r2 = 0.03268; P = 0.2643; visual cortex: r2 = 0.001221; P = 0.8305), therefore discarding PMI as a possible confounding factor. The gene discussed is EPAS1; the disease is multiple system atrophy.