Fatal Familial Insomnia

Reviewed by: HU Medical Review Board | Last reviewed: June 2020

Fatal familial insomnia (FFI) is an extremely rare inherited disease in which a person cannot sleep. Sleeping problems may be mild at first but get worse quickly. Eventually, this lack of sleep causes severe physical and mental issues that lead to coma and death.1

It was first identified in Italian families but has since been found all over the world. It is a prion disease similar to Creutzfeldt-Jakob disease - the human version of mad cow disease. The symptoms are a little different but the way it destroys the brain is similar.2

Who gets fatal familial insomnia?

FFI affects men and women equally. Most people with FFI begin showing symptoms between ages 45 and 50. It has been diagnosed in people as young as 23 and as old as 73.1-2

Symptoms of fatal familial insomnia

Mild insomnia usually starts suddenly and then gets worse quickly over the next few months. When the person does sleep, powerful dreams are common.

The person may be confused when awake, have problems with concentration and memory, or hallucinate. Physical symptoms may include:1-2

  • Unintended weight loss
  • Muscle twitches and jerks, hiccups
  • Lack of muscle control, tremor, or stiffness
  • Slurred speech or trouble swallowing
  • Double vision or jerky eye movement

It is also common for the person to develop a rapid heartbeat, high blood pressure, and fever. Depression and anxiety are common too. In most cases, the person dies in about 13 months.1-2

What causes fatal familial insomnia?

Fatal familial insomnia is most often caused by a gene mutation in the PRNP gene on chromosome 20p13. This gene controls how the PrP prion protein is shaped. In FFI, this toxic protein gets misfolded and builds up in the thalamus, a deep part of the brain.

Eventually, these misfolded proteins destroy the nerve cells that control body functions such as sleep, appetite, and body temperature. The brain tissue develops sponge-like holes or gaps.1-2

If someone carries the FFI mutation, there is a 50 percent chance it will be passed on to their child, regardless of the sex of the child. The chances are the same with each pregnancy. It can be passed through the mother or the father.1

Most people with FFI have a family history of the disease. In rare cases, it will occur spontaneously. This is called sporadic fatal insomnia (SFI). Only about 2 dozen people have ever been reported to have SFI.1

How is fatal familial insomnia diagnosed?

FFI is diagnosed using a combination of tests, family history, and a physical exam. Everyone with FFI will have a mutated PRPN gene, but testing for this gene can only be done in specialized labs.

A sleep study, or polysomnography, can help document the limited sleep times and problems moving through sleep stages. A spinal tap may be needed to look for higher than normal levels of the 14-3-3 protein, which is a sign of nerve cell death.

A PET scan, or positron emission tomography, can create 3-dimensional images of the brain’s activity, including in the thalamus. MRI, or magnetic resonance imaging, and CT scans may help rule out other diseases.

How is fatal familial insomnia treated?

There is no standard treatment or cure for fatal familial insomnia or sporadic fatal insomnia. A team of doctors is needed to manage the condition, including a neurologist, psychiatrist, psychologist, pain specialist, social workers, and more. This team will try to manage symptoms using a combination of anti-seizure drugs and sedatives.1

Genetic testing and counseling is recommended for anyone with FFI or SFI and their families.1

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