Furthermore, Complex I deficiency is often observed in neurons of PD patients [7] and mutations in genes causing familial forms of PD, including pink1 (PARK6, OMIM #605909, Gene ID: 65018), parkin (PARK2, OMIM #600116, Gene ID: 5071) and DJ-1 (PARK7, OMIM #606324, Gene ID: 11315) result in defects in mitochondrial morphology and/or function in model organisms [8]–[14]. Here, PINK1 is linked to Parkinson disease.