COX4I1 and Parkinson disease: Associations between PD and alterations in pathways that regulate lipid metabolism and mitochondrial dysregulation have been identified in an outstanding work by Chi et al. Upon meta-analysis of multiple datasets obtained from the Gene Expression Omnibus database, including substantia nigra and peripheral blood samples, the levels of MAPK8, CDC42, NDUFS1, COX4I1, and SDHC were found to be downregulated [24].