question: What is FFI, fatal familial insomnia
answer: Familial fatal insomnia (FFI) is a prion disease caused by a mutation (D178N-129M haplotype) in the Prion Protein gene (PRNP). FFI is manifested by sleep disturbances with insomnia, autonomic disorders and spontaneous and evoked myoclonus, among other symptoms. FFI is considered to be a rare disease.