PGC-1α and NRF-1 mRNAs are downregulated in the SN and striatum of PD patients, with no changes in mRNA levels of PARIS or Parkin, indicating that the upregulation of PARIS protein levels responds to a loss in the E3 ubiquitin ligase activity of Parkin (Shin et al., 2011). Here, PRKN is linked to Parkinson disease.