Characteristics of Fatal Familial Insomnia

Fatal familial insomnia is a rare disease transmitted from generation to generation. It's a prion disease and is usually deadly.
Characteristics of Fatal Familial Insomnia
Leonardo Biolatto

Written and verified by the doctor Leonardo Biolatto.

Last update: 24 May, 2023

Fatal familial insomnia is a rare genetic disease and its frequency of occurrence is quite low. Thus, people with the condition usually have a family history of the disorder.

Indeed, it’s a hereditary pathology although it may also be due to the prions — abnormal disease-causing proteins. Both factors combine to pass on this prion, carrying the disease from parents to children.

As the name suggests, fatal familial insomnia is the inability to sleep. The causative prions alter the patient’s circadian rhythm to the point of keeping them awake at all times. Of course, the mental and physical strain leads to a kind of coma that ends in death.

Fatal familial insomnia falls within the group of prion diseases called spongiform encephalopathies. Perhaps the best-known disorder of this kind is mad cow disease and it’s definitely similar to this disease in terms of its causes.

The prion activates and the symptoms usually begin between the ages of 30 and 60s. There are records of younger cases, but they’re not the norm. Some families sort of expect it because there’s a history of it.

Causes of fatal familial insomnia

As we have mentioned above, fatal familial insomnia is a prion disease. These originate from a DNA mutation eventually expressed in a defective protein. Then, the prion attacks the neurons and leads to spongiform encephalopathy.

The mechanism of this condition is similar to mad cow disease and Creutzfeldt-Jakob disease; it’s genetic.

The gene-altered by the prion disease is now identified and referred to as PRNP. The altered protein affects the thalamus area, the region that regulates most of the circadian rhythms, especially the sleep-wake cycle. The thalamus progressively degenerates and leads to a coma.

A doctor with a floating brain.
Fatal familial insomnia affects the cerebral thalamus area.

Continue reading and learn about Insomnia: What Not to Do After Being Awake All Night

Symptoms of the disease

The most characteristic sign of fatal familial insomnia is the inability to sleep. A person just can’t do it even when sleepy and tired. Then, they’ll probably enter a period of drowsiness and usually comes out of it agitated, with hallucinations and with changes in their respiratory rhythm.

The persistence of this state leads to a coma. This is because the body needs sleep for the physiology of neurons and other cells to restart and continue in health. The appearance of hallucinations, memory loss, and behavioral changes are a consequence of this lack of rest.

Stress is really high, of course. As you might imagine, a person who doesn’t get a proper night’s rest already feels disturbed and cannot feel at ease. In addition, the change in the circadian rhythm pairs with an increase in the secretion of cortisol, a hormone that generates stress symptoms.

Diagnosing fatal familial insomnia

A woman who can't sleep.
Fatal familial insomnia is genetic.

Diagnosing fatal familial insomnia can be easy or difficult. There’s a well-founded suspicion that there’s a family history of it.

Usually, a person initially consults a physician for insomnia — the inability to fall asleep. Then, they may add to it other symptoms of stress and memory loss. The professional will likely prescribe a sleep study first.

The next complementary method is positron emission tomography, so as to identify metabolic changes in the thalamus. The most frequent finding is a decrease in the metabolic activity of that region due to the degeneration it causes.

Gene identification is now possible thanks to the field of genetics. Today, professionals will also conduct studies on children and grandchildren. It’s the best way to discover the mutation in a family that has a history of fatal familial insomnia before the signs appear.

The most severe insomnia of all

Fatal familial insomnia is a serious disease with no cure. It progressively evolves by destroying the thalamus, causing coma, and ends in death. As you can imagine, the quality of life of these patients is terrible in their last months of life.

Indeed, it’s a rare and infrequent disease so research into it doesn’t attract many followers or large funding. However, there are research groups dedicated exclusively to finding treatments for these people.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

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  • Saa P, Harris DA and Cervenakova L. Mechanisms of prion-induced neurodegeneration. Expert Reveiws in Molecular Medicine. April 8 2016; 18(e5):1-18.
  • Gutiérrez-Amavizca, Bianca Ethel, Jaime Paul Gutiérrez-Amavizca, and Jorge Alberto Pérez-Leóna. “Genetic contribution in primary sleep disorders.” Revista Médica del Instituto Mexicano del Seguro Social 57.1 (2019): 21-29.
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This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.