Fatal familial insomnia (FFI) is an extremely rare autosomal dominant inherited prion disease of the brain. It is almost always caused by a mutation to the protein PrPC, but can also develop spontaneously in patients with a non-inherited mutation variant called sporadic fatal insomnia (sFI). FFI has no known cure and involves progressively worsening insomnia, which leads to hallucinations, delirium, confusional states like that of dementia, and eventually, death. The average survival time for Th...