COX4I1 and Parkinson disease: The genes included in the KEGG pathway of ‘Parkinson's disease’ (hsa05012) were ATP5E, UQCRB, UQCRC1, and UQCRFS1 in the first cohort, and ATP5B, ATP5O, COX4I1, COX8A, NDUFA4L2, NDUFB11, NDUFB2, NDUFB8, NDUFS5, UBE2L3, UQCR11, and UQCRH in the second cohort.