SNCA and Parkinson disease: Once inside the nucleus, α-synuclein appears to bind the promoter of the mitochondrial transcription activator peroxisome proliferator-activated receptor gamma-coactivator 1α (PGC1α) both in vitro, in vivo, and in brain tissue of PD patients, which leads to reduced activity of the PGC1α promoter and reduced levels of PGC1α mRNA and protein [68,69].