According to the Mayo Clinic (2016), insomnia is a sleep disorder characterized by difficulty falling asleep, staying asleep, or getting back to sleep after waking. It can be acute or chronic, and have genetic or environmental causes. Acute insomnia is reported in about 30 percent of the population, while about 10% meet criteria for chronic insomnia (Vargas et al. 2020). Common causes of insomnia include stress, poor sleeping habits, side effects of medications, medical conditions, mental health disorders, caffeine, nicotine, alcohol, and much more (Mayo Clinic 2016). If left untreated, it can lower job performance, slow reaction time, and increase risk for long-term conditions such as high blood pressure. Lifestyle changes, medication, or even cognitive behavioral therapy can have some effect on treating this disorder (Mayo Clinic 2016).
However, there are two types of insomnia which are fatal without a cure: Fatal familial insomnia (FFI) and sporadic fatal insomnia (SFI). These conditions are exceedingly rare. Cracco et al. (2018), notes there are about 70 families worldwide with FFI and 25 published cases of SFI. Your stress and poor habits won’t cause this, but it is important to understand these conditions to understand the impact they have on individuals.
Fatal familial insomnia (FFI) is an inherited neurodegenerative prion disease caused by a gene mutation. Sporadic fatal insomnia (SFI) is thought to manifest from a sporadic mutation of the same gene (Montagna et al. 2003). Simply, FFI is passed through families, and SFI is more of a random occurrence. Both of these conditions come from a D178N substitution caused by a genetic mutation on the prion protein gene (PRNP), and a methionine at codon 129 (Cortelli et al. 1999; Montagna et al. 2003; Cracco et al. 2018).
According to Cracco et al. (2018), FFI and SFI, “...are primarily characterized by progressive sleep impairment, disturbances of autonomic nervous system, and motor signs associated with severe loss of nerve cells in medial thalamic nuclei.” This can be seen by loss of sleep spindles and slow-wave sleep, involuntary twitching or jerking (myoclonus), ataxia, and dysphagia. Later on, PET scans show hypometabolism in the thalamic and limbic regions of the brain (Montagna et al. 2003). The primary difference is SFI having a longer disease duration and more neuropsychiatric symptoms than FFI (Chen et al. 2023).
Insomnia is a detrimental disorder when left untreated. Fatal familial insomnia and sporadic fatal insomnia cross the line from a disorder to a severe, incurable disease. These conditions, stemming from a genetic mutation, progress from sleep impairment to severe neurological effects. This leads to permanent neuron degeneration, and eventually death. Recognizing the existence of these disorders helps bring awareness and new medical research to these affected individuals. As science progresses, it may find a way to make these diseases non-fatal.
References
Chen Z, Chu M, Zhang J, Kong Y, Xie K, Cui Y, Ye H, Liu L, Li J, Wang L, et al. 2023. Clinical profiles and ethnic heterogeneity of sporadic fatal insomnia. Eur J Neurol. 30(4):813–822. doi:10.1111/ene.15676.
Cortelli P, Gambetti P, Montagna P, Lugaresi E. 1999. Fatal familial insomnia: clinical features and molecular genetics. J Sleep Res. 8 Suppl 1:23–29. doi:10.1046/j.1365-2869.1999.00005.x.
Cracco L, Appleby BS, Gambetti P. 2018. Fatal familial insomnia and sporadic fatal insomnia. Handb Clin Neurol. 153:271–299. doi:10.1016/B978-0-444-63945-5.00015-5.
Mayo Clinic [Internet]. 2016. Insomnia. Mayo Clinic. [cited 2024 Jan 10]. Available from: https://www.mayoclinic.org/diseases-conditions/insomnia/symptoms-causes/syc-20355167
Montagna P, Gambetti P, Cortelli P, Lugaresi E. 2003. Familial and sporadic fatal insomnia. The Lancet Neurology. 2(3):167–176. doi:10.1016/S1474-4422(03)00323-5.
Vargas I, Nguyen AM, Muench A, Bastien CH, Ellis JG, Perlis ML. 2020. Acute and Chronic Insomnia: What Has Time and/or Hyperarousal Got to Do with It? Brain Sciences. 10(2):71. doi:10.3390/brainsci10020071. Assessed and Endorsed by the MedReport Medical Review Board