PRNP and early-onset autosomal dominant Alzheimer disease: A third group of diseases related to amyloid deposits concerns neurodegenerative diseases, such as amyloid β (Aβ) in Alzheimer’s disease (AD), α-synuclein (α-syn) in Parkinson’s disease (PD), or prion protein (PrP) in Creutzfeldt–Jakob disease, which are the most studied amyloidoses due to their major clinical impacts [8].