Fatal insomnia

Fatal familial insomnia (FFI) is a prion disease. It always causes death. Victims will suffer from symptoms that include: severe insomnia (lack of sleep that gets worse), memory loss, hallucinations (seeing/hearing stuff that is not really there), and involuntary muscle twitching or jerking (myoclonus).

Causes of FFI

FFI is caused by a change (mutation) in the PRNP gene. This gene makes the prion protein PrPc.

The gene is inherited in an autosomal dominant pattern (meaning that only one of the mutated gene from a parent is needed to cause the disease).

Diagnosing FFI

FFI can be diagnosed by the following tests:

• Polysomnography (sleep test)
• Genetic Testing: testing that looks for a specific mutation in the PRNP gene
• Brain imaging, such as
  • PET scan: shows how well the thalamus in the brain is working
  • MRI: shows a detailed image of the brain
  • EEG: records brainwave activity to look for abnormalities
• Cerebrospinal Fluid (CSF) analysis: looks at the fluid around the brain and spinal cord

Treatments for FFI

Because there is no cure for FFI, treatment is focused on controlling symptoms and decreasing the discomfort of the person with FFI.

The following are treatments for FFI.

• Medications for activating deep sleep (gamma-hydroxybutyrate and phenothiazines)
• Drugs such as clonazepam for controlling muscle spasms
• Vitamins such as iron and B6
• Psychosocial therapy
• Hospice care during the last stage of the disease

Fatal Insomnia Media

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  Idiogram of chromosome 20 showing gene PRP location

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  Timeline of a fatal familial insomnia (FFI) patient

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  Hypnogram comparing the sleep pattern of a healthy control with five FFI patients, who display decreased sleep efficiency and disrupted sleep cycles (W: wake; R: REM; N1-3: NREM sleep stages.)