Systems biology analysis of human brains revealed a pervasive expression defect of PGC-1α-linked bioenergetics genes in laser-captured dopamine neurons of Parkinson's patients and substantia nigra of individuals with subclinical, brainstem-predominant Lewy body neuropathology [14] that likely represent preclinical PD [36]. Here, PPARGC1A is linked to Parkinsonism.