Prion-associated diseases are also known as transmissible spongiform encephalopathies, or TSEs. TSEs of humans include kuru, Creutzfeldt–Jakob disease, Gerstmann–Sträussler–Scheinker syndrome, fatal familial insomnia, variably protease-sensitive prionopathy, and familial spongiform encephalopathy. Unlike other infections, the transmissible material for all TSEs is aberrantly folded proteins. As a group, these disorders cause progressive impairment of central nervous system function that manifests as memory loss, personality changes, and/or abnormal movements. TSEs are progressive, incurable, and ultimately fatal. The term “spongiform encephalopathy” is derived from the classic post-mortem histologic findings of tiny, sponge-like holes found throughout the cerebral cortex in the brains of afflicted individuals.