PRNP and neurodegenerative disease: Prion diseases, such as Creutzfeldt–Jakob disease (CJD), are also fatal neurodegenerative diseases, involving the conformational conversion of a normal cellular prion protein (PrPc) into a pathogenic one (PrPsc), which tends to form aggregates and amyloid fibrils, which, in turn, promote the abnormal folding and aggregation of normal PrPc [142].