What Triggers Fatal Familial Insomnia?

Medically Reviewed on 11/29/2022
Fatal Familial Insomnia
Fatal familial insomnia is a rare, hereditary sleep disorder that eventually causes death.

Fatal familial insomnia is associated with difficulty sleeping, cognitive issues, and various other symptoms that worsen over time. It is extremely rare and, with time, may cause death.

Fatal familial insomnia is caused by a faulty variant of the prion-related protein (PRNP) gene inherited from the affected parents. Rarely, someone may develop fatal familial insomnia with neither of their parents carrying the mutated PRNP gene.

What is fatal familial insomnia?

Fatal familial insomnia is a hereditary sleep disorder that is reported in only 70 families worldwide.

Fatal familial insomnia is a progressive neurodegenerative disorder that causes sleeping difficulties and other symptoms associated with poor sleeping habits. It is named because the condition causes death within a year or two after the symptoms start. Symptoms may vary among people.

There are two different types of fatal insomnia:

  1. Fatal familial insomnia: The condition is a rare genetic disorder caused by the genetic mutation of the prion-related protein (PRNP) gene, resulting in abnormalities in prion proteins. These prion proteins accumulate in the thalamus of the brain and result in progressive damage to nerve cells or neurons. There is a 50 percent risk of passing the abnormal gene from the affected parent to the child with each pregnancy regardless of the child’s gender.
  2. Sporadic fatal insomnia: Sporadic fatal insomnia is not inherited. It is even rarer than fatal familial insomnia. Only 25 documented cases of this disorder have been reported globally as of 2018.

What are the symptoms of fatal familial insomnia?

The initial symptoms are insomnia (inability or difficulty sleeping) and vivid dreams.

When the disease progresses, it causes:

4 stages of fatal familial insomnia

From the onset of symptoms to the last stage, the average time is 18 months. In some people, the total period could be 7 months or sometimes, 78 months.

Sporadic fatal insomnia lasts longer, on average 30 months, from the onset of symptoms to death.

The four stages of fatal familial insomnia include:

  1. Stage I: Lasts for three to six months. The primary symptoms include difficulty sleeping and unusual dreams. Symptoms worsen and psychological symptoms, such as panic attacks and paranoia, may begin.
  2. Stage II: Lasts for five to nine months. The symptoms, such as mood changes, may worsen, and anxiety and depression may start. Other symptoms, such as increased heart rate, sweating, breathing difficulties, and trouble moving and walking, could begin.
  3. Stage III: Lasts for three months. The sleep cycle disrupts, and sleeping could be very difficult.
  4. Stage IV: Lasts up to six months. The sleep disturbances get worse, leading to dementia, other severe symptoms and coma, and then death.


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What are the ways to diagnose fatal insomnia?

Fatal insomnia can be diagnosed using the following:

  • Gene testing: If there is a genetic mutation in the prion protein or PRNP gene, fatal familial insomnia is confirmed. A genetic mutation does not cause sporadic fatal insomnia, so gene testing is not recommended for sporadic fatal insomnia.
  • Sleep study: Medical professionals conduct a sleep study called polysomnography. People with fatal insomnia have shorter periods of sleep and rapid eye movement sleep. Polysomnography determines a drastic decline in sleeping patterns.
  • Brain scans: Positron emission tomography helps see the activity of the thalamus region of the brain that is affected by fatal insomnia. MRI helps find out atrophy (damage) in the brain.

How to treat fatal familial insomnia

There is no cure for fatal familial insomnia.

A few treatment options may relieve the symptoms, such as:

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Medically Reviewed on 11/29/2022
Image Source: iStock image

Fatal Insomnia. https://www.sleepfoundation.org/insomnia/fatal-insomnia

What Is Fatal Familial Insomnia? https://www.webmd.com/brain/what-is-fatal-familial-insomnia

Fatal Familial Insomnia. https://rarediseases.org/rare-diseases/fatal-familial-insomnia/