Peculiarities of Prion Diseases

Prion diseases (PrDs) are transmissible and fatal neurodegenerative diseases naturally occurring in humans and animals, ‘‘mad cow’’ disease being the most infamous. Their development and propagation requires endogenous prion protein (PrP) and derives from the conversion of PrP to a misfolded form, which combines with other misfolded PrP molecules to form small nuclei (seeds). The seeds can then result in an exponential increase in additional misfolded PrP molecules, eventually accumulating into large aggregates. However, the physiological roles of normal and misfolded PrP, mechanisms of the conformational transition, and the associated nature of the infectious and neurotoxic agents still remain enigmatic. In this review, we address five questions regarding PrDs that we are frequently asked by laypeople and scientists new to the field.