brain, spinal cord, and nerve disorders
Fatal Insomnia
Introduction
Fatal insomnia is a rare prion disease that interferes with sleep and leads to deterioration of mental function and loss of coordination. Death occurs within a few months to a few years. (See also Overview of Prion Diseases .) Fatal insomnia has two forms: Familial:This form, called fatal familial insomnia, is inherited. It is due to a specific mutation in the gene for a normal protein called cellular prion protein (PrPC). Sporadic:This form occurs spontaneously, without a genetic mutation. Fatal familial insomnia and sporadic fatal insomnia differ from other Overview of Prion Diseases because they affect predominantly one area of the brain, the thalamus, which influences sleep. In fatal familial insomnia, symptoms may begin in a person's late 20s to the early 70s (average is 40 years). Death usually occurs 7 to 73 months after symptoms begin. The sporadic form begins slightly later, and life expectancy is slightly longer. 