ABSTRACT
Prion diseases are a closely related group of fatal neurodegenerative disorders that affect humans and other mammals [Collinge, 2001]. They have also been called transmissible spongiform encephalopathies (TSEs), slow virus diseases, and subacute spongiform encephalopathies. A unique feature of these diseases is that they can have three different origins: sporadic, inherited, and infectious. The clinical, epidemiological, and neuropathological features can be very different in each of the diseases, but they are classified together because the key molecular event appears to be the same, i.e., the misfolding of the prion protein [Collinge, 2001; Prusiner, 1998]. This chapter provides an overview of the main characteristics of different forms of prion diseases, describing their origin, clinical symptoms, prevalence, and neurological alterations.
