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Fatal Familial Insomnia (FFI) is an extremely rare genetic neurodegenerative disease that leads to severe sleeping difficulties, dementia, and involuntary muscle twitching. The disease, which has no known cure, worsens over time and can be fatal within a few years after symptoms begin.
What Causes Fatal Familial Insomnia?
FFI is caused by a mutation in the PRNP gene, which produces prion proteins. These prions are abnormal versions of normal proteins, and their misfolded shape leads to cellular damage, especially in neurons within the brain. Specifically, the thalamus, which plays a critical role in regulating sleep, temperature, appetite, and other bodily functions, is severely affected.
The condition is passed from parent to child in an autosomal dominant pattern, meaning that an individual only needs to inherit one copy of the mutated gene to develop FFI. Though the disease typically runs in families, it can also occur in individuals without a family history due to spontaneous mutations in the PRNP gene.
Who is Affected by Fatal Familial Insomnia?
FFI is incredibly rare, affecting only 1 to 2 individuals per million people each year, according to the National Organization of Rare Disorders (NORD). Between 50 to 70 families worldwide are thought to carry the genetic mutation responsible for the condition.
Symptoms of Fatal Familial Insomnia
The hallmark symptom of FFI is insomnia, which begins with difficulty falling asleep and progresses to a complete inability to sleep. As the disease advances, other symptoms emerge, including:
- Memory loss
- Hallucinations
- High blood pressure
- Involuntary muscle twitching (myoclonus)
- Excessive sweating
- Loss of coordination and concentration
These symptoms typically begin around the age of 40, though they can start as early as the 20s or as late as the 70s. Over time, patients may fall into a coma-like state and usually die within 9 to 30 months of symptom onset.
Diagnosis and Treatment
There is currently no cure for Fatal Familial Insomnia, and the disease is fatal. However, some treatments may help slow down the progression of symptoms, though these interventions are temporary and do not halt the disease’s progression.
