What causes Fatal familial insomnia ?
What causes fatal familial insomnia? Fatal familial insomnia (FFI) is caused by a specific change (mutation) in the PRNP gene. PRNP encodes the prion protein. Although the exact function of this protein is unknown, scientists suspect that it plays an important role in the brain. Mutations in the PRNP gene result in an abnormal form of the protein that clumps together and accumulates in the brain. This leads to the destruction of neurons (brain cells) and creates tiny holes in the brain, which give the brain a "sponge-like" appearance when viewed under a microscope. The progressive loss of neurons leads to the many signs and symptoms of FFI.