Prionii

Prionii are a class of proteins that can fold in multiple abnormal three-dimensional shapes. These misfolded prion proteins, often referred to as PrPSc, can induce normal prion proteins, known as PrPC, to misfold into the abnormal shape. This process is thought to be contagious and can lead to a class of neurodegenerative diseases called transmissible spongiform encephalopathies (TSEs). Examples of TSEs in humans include Creutzfeldt-Jakob disease (CJD), kuru, and fatal familial insomnia. In animals, TSEs include bovine spongiform encephalopathy (BSE), commonly known as mad cow disease, and scrapie in sheep.

The mechanism by which PrPSc causes disease involves its accumulation in the brain, leading to the formation of amyloid plaques and spongiform changes, which are characterized by the presence of holes in brain tissue. These structural changes disrupt normal brain function and ultimately lead to neuronal death. Prion diseases are invariably fatal and currently have no known cure or effective treatment. The incubation periods for these diseases can be long, ranging from years to decades. Transmission of prions can occur through ingestion of contaminated tissues, medical procedures involving contaminated instruments, or, in some cases, through genetic predisposition. Research into understanding prion biology and developing therapeutic strategies is ongoing.