REL and Parkinson disease: The c-Rel protein is a transcriptional regulator for mitochondrial antioxidant and antiapoptotic factors, therefore, the reduction of its physiological production could contribute to OS in PD [77]; while mutations of the LLRK2 enzyme in PD would seem related to mitochondrial ROS production, thus suggesting the involvement of this enzyme in the regulation of OS and mitochondrial dysfunction [78].