Prion diseases

The prion diseases (PrDs) have received considerable attention in recent years, primarily as a result of heightened concern about the risk that bovine spongiform encephalopathy (mad cow disease) and other animal borne PrDs pose to humans. Although rare, the PrDs represent an important group of dementias that behave as both neurodegenerative and infectious diseases. The following review details the clinical and pathologic phenotypes of the major expressions of PrD in humans and the current approach to their diagnosis. The historical aspects leading to the recognition of these diseases and the theories regarding the pathogenesis and the transmissible nature of prions are also addressed. (C) 2004 Elsevier B.V. All rights reserved.