Prion proteins are responsible for a group of invariably fatal neurodegenerative diseases known as Transmissible Spongiform Encephalopathies (TSE). These include Creutzfeldt-Jakob Disease (CJD), Bovine Spongiform Encephalopathy (BSE, also known as "mad cow disease"), and Scrapie in sheep. The hallmark of these diseases is the formation of sponge-like holes in brain tissue, leading to severe neurological symptoms and death.
