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Fatal Familial Insomnia: When Genes Decide How You Sleep

NeurologyMrMed

04 Mar 2022

MrMed

4 Min. Read

Last updated on 25 Apr 2026

Can genes determine how you sleep? Yes, but it is extremely rare. Sleepless nights or irregular sleep patterns constitute insomnia, but if these sleep disturbances progress over time to the point of movement restriction and problems in thinking, it could indicate something more serious, like fatal familial insomnia. Let us learn about fatal familial insomnia, its symptoms, causes, diagnosis and treatment.


What Is Fatal Familial Insomnia?

Fatal familial insomnia is a rare, genetic brain disorder, characterized by inability to fall asleep. Initially the symptoms will be mild but it gradually worsens over time. 

Our autonomic nervous system takes care of automatic body processes like body temperature, breathing, sweating and heart rate. But, when a person is diagnosed with fatal familial insomnia, his/her autonomic nervous system gets affected to a great extent. As a result, their health deteriorates physically and mentally.

Difference Between Insomnia And Fatal Insomnia:

Unlike insomnia which is a sleep disorder, fatal insomnia is a neurodegenerative disease that causes sleep troubles and other symptoms that become worse over time. Fatal insomnia is a prion disease that progresses through various stages starting from insomnia and the survival time is said to be an average of 18 months. Hence, what works for insomnia does not work for fatal insomnia.

 

What Causes Fatal Familial Insomnia?

Fatal insomnia is a result of accumulation of several misfolded prion proteins in the brain and hence it is referred to as prion disease. Genetic alteration is the primary cause of fatal insomnia. The main gene involved in this disease is PNRP gene, which is one of the prion proteins. Misfolding of the PNRP gene occurs primarily in the thalamus part of the brain.

The main function of the PNRP gene is apparently transporting copper into the brain cells to prevent brain injury. Alterations in PNRP genes result in fatal insomnia. If only one parent has this gene alteration, the child has a 50% chance of inheriting this gene and developing the disease.


How Do I Know If I Have Fatal Familial Insomnia?

Early symptoms include mild difficulties in sleeping, muscle spasms and stiffness. Usually, the symptoms of fatal familial insomnia begin at ages between 40 and 60 years and get worse over time. People kick and move a lot during sleep and thus sleep disturbance occurs. This slowly progresses to mental disturbances and lack of coordination in movement. Some of the symptoms include:

  • Inability to fall asleep or stay asleep

  • Difficulty thinking and concentrating

  • Short-term memory loss

  • Weight loss

  • Difficulty in coordinating movements

  • High blood pressure

  • Excessive sweating

  • Inability to maintain body temperature

  • Rapid breathing and heartbeat

  • Trouble paying attention

  • Double vision

  • Trouble swallowing

  • Difficulty speaking

  • Vivid dreaming

  • Constipation

  • Sexual dysfunction

  • Mood changes


Diagnosis Of Fatal Familial Insomnia

Before confirming your diagnosis, your healthcare provider will assess your medical history and thoroughly conduct a clinical evaluation to rule out other disease possibilities. Some of the highly preferred tests for evaluating include:

  • Positron emission tomography: This is an advanced imaging technique beneficial for diagnosing FFI. The findings from this imaging test might be helpful in detecting the early stages of the disease. This test produces a three-dimensional image of the brain that shows how well the thalamus part of the brain is functioning and reveals the metabolism of the brain.

  • Routine CT scan and MRI: They reveal changes in the thalamus part of the brain structure. These tests are not as effective as others in diagnosing fatal insomnia, but they help in ruling out other disease possibilities.

  • Polysomnography: This is called sleep study. It is a test indicated to check the abnormalities in the sleep pattern.

  • Genetic testing: Molecular genetic testing detects an abnormal variant in the PNRP gene, but such testing facilities are available only in a few specialized laboratories.


Is There A Cure For Fatal Familial Insomnia?

Fatal familial insomnia is incurable. The treatment focuses primarily on the symptoms. Certain symptoms like muscle spasms and sleeplessness can be treated with appropriate medications. Amphotericin B is also being tested in clinical trials for its efficacy in treating symptoms. However, further research is yet to be conducted to discover a potential cure for this disease. 


The treatment approach requires collaboration of physicians from various health disciplines such as neurology, pain management and so on. The initial approach to treatment will be discontinuing medications that have the tendency to cause sleep or memory disturbances. Your healthcare provider will suggest a healthy diet plan to gain nutrients through food. If you have swallowing difficulties, you might need to use a feeding tube.


Some Approaches That Help:

Psychosocial therapy is intended for patients and caretakers to cope with this condition. Speaking with a therapist about fatal insomnia diagnosis can help patients and family members deal with the emotions related to the disease. 

Medications like gamma hydroxybutyrate, antipsychotics and sedatives help improve sleep duration. Vitamin and melatonin supplements improve wellness in fatal insomnia. Discuss with your physician before taking these medicines for your insomnia.

Disclaimer: This content is for informational purposes only and should not be considered medical advice, diagnosis, or treatment. Fatal Familial Insomnia is a rare and serious neurological condition that requires expert medical evaluation. If you or someone you know has concerning symptoms, consult a qualified healthcare professional promptly.

Details about the author of this blog

Dr. Bhairavi S

Dr. Bhairavi S

Writer - Medical Communications

Dr. Bhairavi S, RPh is a dedicated medical writer and Pharm D with over four years of professional experience in healthcare communication. She currently develops medical communications content, focusing on article writing, infographics, and CME materials for a community of 380,000+ doctors, supporting evidence-based clinical education. Previously, she served as Medical Content Writer at MEDICCA PRESS Limited, creating CME modules and scientific newsletters (Jan 2023–Feb 2025), and freelanced on prescribing information and healthcare materials (Aug–Nov 2022). At MrMed (Mar 2021–Apr 2022), she refined her expertise in medical proofreading and content accuracy. She also gained clinical experience as a Clinical Pharmacist intern at SRM Medical College Hospital & Research Centre (Jun 2019–Jun 2020). Dr. Bhairavi excels in manuscript writing, literature reviews, and CME development, and is keen to advance in scientific research and medical writing.

Details about the reviewer

Dr. Tejashwin Adiga

Dr. Tejashwin Adiga

Surgery Resident @ Apollo Hospitals, Chennai

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Tags:

fatal insomnia
genetic insomnia
sleeplessness
familial insomnia
sleep disorders

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