Prion diseases.

Prion diseases are a group of disorders sharing clinical and pathological features. Many of the enigmas of these diseases have now yielded to the concerted effort to understand them and their unusual pathogenesis. The genetic backgrounds of the various diseases are being clarified at an impressive rate, but the cause of sporadic Creutzfeldt-Jakob disease, the most frequently occurring human prion disease, is still not understood at all. The mechanisms underlying the evolution of the disease, as well as the species barrier are better understood.