PRNP and human prion disease: Prion diseases, also known as transmissible spongiform encephalopathies (TSEs), encompass a group of rare neurodegenerative conditions secondary to abnormal conversion of a constitutively expressed cellular glycoprotein, the prion protein (PrPC), into an abnormally folded isoform (PrPsc) (Geschwind, 2016; Zanusso et al., 2016).