Prion diseases are known to be?

Prion diseases are indeed classified as fatal due to the progressive degeneration they cause in the brain, leading to severe neurological impairment and ultimately death. These diseases, which include conditions such as Creutzfeldt-Jakob disease (CJD) and Mad Cow Disease (BSE), are caused by misfolded proteins known as prions that induce abnormal folding in normal proteins within the brain. This results in a range of devastating symptoms including cognitive decline, motor dysfunction, and ultimately, death typically within months to a few years after symptoms begin. The mechanism of prion diseases involves the accumulation of these misfolded proteins, which is irreversible and leads to neurodegeneration.

Prion diseases are not reversible; there are no known effective treatments that can halt or reverse the progression once the diagnosis is made. They are also relatively rare and not commonly seen in children; the majority of cases occur in adults. Therefore, the fatal nature of prion diseases is a hallmark characteristic that significantly affects patient outcomes.