Interestingly, mitochondrial complex 1 deficiency has been reported in the substantia nigra of PD patients (Schapira et al., 1989), and is widely associated with increased mitochondrial ROS production, oxidative stress, reduced mitochondrial membrane potential, and mitophagy, along with α-synuclein pathology observed in multiple PD models (Devi et al., 2008; Hsu et al., 2000; Ludtmann et al., 2018). This evidence concerns the gene SNCA and Parkinson disease.