Medically reviewed by
Dacelin St Martin, MD
Triple board-certified in Sleep Medicine,
Internal Medicine, and Pediatrics.
Fatal familial insomnia is a rare inherited degenerative brain condition. It’s marked by an inability to sleep (insomnia) that starts moderately but quickly develops, resulting in considerable physical and mental decline.
Fatal insomnia, despite its name, is not a sleep disorder. Instead, it’s a prion disease that causes degenerative nerve illness, resulting in sleep problems and other symptoms that worsen with time. Prion diseases result from an abnormality in the prion protein found in the human body.
These defective prions build up in a portion of the brain called the thalamus, responsible for sleep regulation. The buildup of prions in the brain injures it, resulting in brain and nerve impairment symptoms and could even cause coma or death.
How Common Is Fatal Familial Insomnia?
If you have trouble falling or staying asleep, it is doubtful that you have fatal familial insomnia.
Experts think that only individuals in 70 families across Europe, the United States, China, Japan, and Australia are carriers of the disease-causing gene.
Generally, prion diseases are infrequent. Scientists estimate that approximately one person per million members of the general population is affected annually by prion disorders.
Because rare diseases are frequently misdiagnosed or undiagnosed, it’s challenging to determine the accurate number of people living with fatal familial insomnia in the general population.
Fatal familial insomnia is caused by the accumulation of misfolded prions in the brain.
A hereditary mutation of the prion protein (PRNP) gene is responsible for the abnormalities in prion proteins seen in fatal familial insomnia (FFI). Because of this, the condition is hereditary, which means that it is passed down through families.
The inheritance pattern of fatal familial insomnia indicates that a child with one parent having the genetic mutation has a 50 percent probability of inheriting it.
Sometimes, some individuals can develop these misfolded prion proteins, although they do not have the genetic mutation associated with it.
Individuals who experience this have sporadic fatal insomnia, a rarer condition than fatal familial insomnia.
The symptoms of fatal familial insomnia can sometimes vary. However, sleep disturbances and vivid dreams are frequently the initial manifestations of the illness.
Typically, insomnia starts in middle age; however, it can begin earlier or later in life.
Sleeplessness may start mildly, but it gradually worsens until the affected person gets very little sleep. It usually comes on unexpectedly and gets worse quickly over the next few months.
Additionally, when people living with fatal familial insomnia fall asleep, they may have vivid dreams.
Sleep deprivation associated with fatal familial insomnia causes physical and mental decline; the disease can progress to coma and death. Other symptoms of fatal familial insomnia include:
- Fast heartbeat
- Breathing quickly
- Sweating excessively
- Elevated blood pressure
- Attention and memory problems
- Body temperature control troubles
- Mood swings
- Loss of weight
- Vision problems
- Having difficulty swallowing
- Speaking difficulties
Many of these symptoms start after experiencing insomnia. The symptoms of sporadic fatal insomnia are comparable to those of fatal familial insomnia; however, they progress differently.
Fatal insomnia can be difficult to diagnose based on the symptoms alone, especially in the absence of a family history of the condition.
Nonetheless, many researchers have outlined potential criteria for diagnosing fatal familial insomnia.
One of the requisite criteria is that you must complain of sleep problems or exhibit sleep disturbances on a sleep study to be diagnosed with this condition.
According to another set of criteria, you need to exhibit at least two types of neurodegenerative symptoms;
- Psychiatric symptoms, including hallucinations, anxiety, depressed mood, and personality shifts
- Problems with physical movements
- Vision problems, including double vision
- Involuntary muscle twitching
- Cognitive or memory difficulties
You may also experience one of the following symptoms: weight loss, voice changes, profuse sweating, fast heart rate, and difficulty regulating body temperature.
You should see your doctor if you have these symptoms because you may have fatal familial insomnia. Your doctor will require you to take some blood tests to rule out other potential causes of the symptoms, such as vitamin deficiencies and thyroid troubles.
There are no curative treatments for fatal insomnia. Currently, treatments are categorized as palliative care, which focuses on providing relief to individuals with this disease. The exact type of palliative care will depend on your doctor and what works best for you. Treatment options for fatal familial insomnia include:
- Multivitamin supplements: Vitamin B6, B12, iron, and folic acid supplementation has been shown to improve the health of individuals with fatal insomnia.
- Melatonin Supplementation: People with fatal insomnia have lower melatonin levels, a sleep hormone. Melatonin supplementation may aid in sleep induction and improve quality of life.
- Healthy Diet: Your doctor may recommend prioritizing the consumption of nutrient-rich foods to obtain vitamins. Also, tryptophan-containing dairy products may promote sleep.
- Stopping Some Drugs: Your doctor may need you to slowly stop taking any drugs that could cause more memory loss, confusion, or insomnia.
- Sedatives: Studies on sedatives to treat fatal insomnia have shown mixed results. Some people with fatal insomnia have found short-term relief by taking certain sedatives with anti-anxiety drugs. Still, other research shows that sedatives have no effect.
- Gamma-Hydroxybutyrate (GHB): A study revealed that it induces slow-wave sleep in individuals with fatal familial insomnia.
Research has been ongoing on potential therapies for fatal insomnia in recent years.
Doxycycline, an antibiotic that affects prion proteins, is relevant due to its ability to postpone the onset of fatal familial insomnia symptoms.
Also of interest to some researchers is how certain types of vaccines could potentially prevent prion disorders.
When Should You See Your Doctor?
If you are having trouble sleeping or find that you are sleepy during the day, you should make an appointment with your doctor as soon as possible.
Despite this, it is essential to remember that fatal familial is rare, and your sleep problems may likely be due to other causes.
The symptoms of fatal insomnia are comparable to those of other conditions, such as dementia and Alzheimer’s disease.
Make an appointment with your physician if you have chronic insomnia accompanied by mental, cognitive, or movement problems.
- “Fatal Familial Insomnia.” NORD (National Organization for Rare Disorders), 15 Mar. 2022, https://rarediseases.org/rare-diseases/fatal-familial-insomnia/
- Geschwind, M. D. (2015). Prion diseases. Continuum (Minneapolis, Minn), 21(6 Neuroinfectious Disease), 1612–1638. https://pubmed.ncbi.nlm.nih.gov/26633779/
- Cracco, L., Appleby, B. S., & Gambetti, P. (2018). Fatal familial insomnia and sporadic fatal insomnia. Handbook of Clinical Neurology, 153, 271–299. https://pubmed.ncbi.nlm.nih.gov/29887141/
- Zerr, I., Schmitz, M., Adam, M. P., Ardinger, H. H., Pagon, R. A., Wallace, S. E., Bean, L. J., Mirzaa, G., Amemiya, A., editors. Genetic prion disease. GeneReviews [Internet]. https://pubmed.ncbi.nlm.nih.gov/20301407/
- Blase, J. L., Cracco, L., Schonberger, L. B., Maddox, R. A., Cohen, Y., Cali, I., & Belay, E. D. (2014). Sporadic fatal insomnia in an adolescent. Pediatrics, 133(3), e766–e770. https://pubmed.ncbi.nlm.nih.gov/24488737/
- Moody, K. M., Schonberger, L. B., Maddox, R. A., Zou, W.-Q., Cracco, L., & Ignazio, C. (2011). Sporadic fatal insomnia in a young woman: A diagnostic challenge: Case report. BMC Neurology, 11, 136. https://pubmed.ncbi.nlm.nih.gov/22040318/
- Krasnianski, A., Juan, P. S., Ponto, C., Bartl, M., Heinemann, U., Varges, D., Schulz-Schaeffer, W. J., Kretzshmar, H. A., & Zerr, I. (2014). A proposal of new diagnostic pathway for fatal familial insomnia. Journal of Neurology, Neurosurgery, and Psychiatry, 85(6), 654–659. https://pubmed.ncbi.nlm.nih.gov/24249784/
- Damavandi, P. T., Dove, M. T., & Pickersgill, R. W. (2017). A review of drug therapy for sporadic fatal insomnia. Prion, 11(5), 293–299. https://pubmed.ncbi.nlm.nih.gov/28976233/
- Burchell, J. T., & Panegyres, P. K. (2016). Prion diseases: Immunotargets and therapy. ImmunoTargets and Therapy, 5, 57–68. https://pubmed.ncbi.nlm.nih.gov/27529062/