PRNP and Parkinson disease: In addition to the progressive death of neurons, neurodegenerative diseases cause accumulation of aberrantly-folded “key” disease proteins (Morales and Green, 2009; Aguzzi and O'Connor, 2010; Perry et al., 2012), which individually characterize each of these conditions, including amyloid β in Alzheimer's disease (AD), α synuclein in Parkinson's disease (PD) and prion protein (PrPSc) in prion diseases such as Creutzfeldt-Jakob disease (CJD) (Prusiner, 1982; Olanow and Prusiner, 2009).