CYBB and Parkinson disease: Furthermore, our demonstration that three of the NADPH oxidase subunits, Nox2, p47phox, and p67phox are present in dopaminergic neurons in substantia nigra adds credence to a neuron cell autonomous contribution to the loss of nigral neurons in PD; a contribution that is over and above the known role of Nox2, p47phox, and p67phox in microglial production of superoxide-induced cell death.