Fatal familial insomnia, FFI, fatal familial insomnia is a prion disease of the brain. It is a rare disease. It is a genetic disease. In fatal familial insomnia (FFI), the thalamus, the part of the brain that controls the sleep-wake cycle, is affected.

Fatal familial insomnia, FFI, fatal familial insomnia is a prion disease of the brain. It is a rare disease. It is a genetic disease. In fatal familial insomnia (FFI), the thalamus, the part of the brain that controls the sleep-wake cycle, is affected. The following symptoms are seen. These symptoms tend to worsen over time. Symptoms usually begin to appear in adulthood. There are two types:

  1. Autosomal dominant fatal familial insomnia
  2. Sporadic fatal insomnia caused by a mutation that is not inherited

The hereditary form is responsible for almost all. It is caused by a mutation in codon 178 of the PRNP gene in humans. This mutated protein is found in only about fifty families worldwide. If only one parent has the gene for this disease, 50% of the children to be born have the risk of carrying this disease. This mutation occurs in the thalamus region of the brain that regulates sleep and causes the disease to progress by breaking the communication between the brain and the body regarding sleep.

What are the symptoms of the disease?

Usually the first symptoms appear around the age of 50. Symptoms may differ from person to person.

  • Stage one: Increasing insomnia leads to panic attacks, paranoia and fears.
  • Second stage: Hallucinations and panic attacks become evident.
  • Third stage: The above symptoms are followed by extreme insomnia, rapid weight loss.
  • Fourth stage: At this stage, the thalamus region of the patient’s brain has begun to fail. The patient has complete insomnia. The patient is unresponsive and has lost the ability to speak, so there is a condition called dementia and this is the final stage followed by death.

Other symptoms include excessive sweating, dry mouth, tremor, stiff neck, high blood pressure, increased heart rate, constipation. However, patients do not lose their communication skills even in the advanced stages of the disease and continue to understand the environment.



The characteristic symptom in FFI disease is progressive insomnia. Insomnia usually begins in middle age, although it may rarely occur earlier or later. Insomnia may be mild at first, but gradually worsens over time. Insomnia often begins suddenly. It can get worse quickly over the next few months. Insomnia leads to physical and mental deterioration, and the disease eventually progresses to coma and death.

Although insomnia is often the first symptom, some patients may experience problems with thinking, cognition, memory, language and behavior, and progressive dementia in the early stages. Initially, unintended weight loss, forgetfulness, inattention, problems concentrating, or speech problems may occur. Episodes of confusion or hallucinations may ensue.

How is the disease diagnosed?

The patient’s complaints and clinical findings warrant suspicion of fatal familial insomnia. In addition, further examinations such as sleep test and computerized positron emission tomography are performed to confirm the diagnosis.

Other prion diseases should also be considered in the differential diagnosis.

How is the disease treated?

There is no known cure. Drug therapy may cause sudden coma development in patients. Therefore, no drug treatment can be applied. Supportive care is applied in the treatment. Sleeping drugs (including barbiturates) have not been shown to be beneficial; on the contrary, it is known to worsen symptoms and accelerate their course in more than half of patients. Genetic therapy studies continue. The end of the disease is always death. Life expectancy varies between 7 months and 6 years, with an average of 18 months.

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