Symptoms of rare brain disorder that stops people being able to sleep and eventually kills them

There's nothing worse than struggling to sleep, especially when you're super tired.

But, there's actually a brain disorder which eventually leads to losing the ability to sleep altogether and results in death.

Fatal familial insomnia (FFI) is an extremely rare genetic condition which impacts the nervous system and brain. Only one to two people per million have FFI and the symptoms could be difficult to spot.

Fatal familial insomnia is a rare genetic condition (Getty Stock Images)

What causes fatal familial insomnia?

FFI is caused by a mutation or change of the prion-related protein gene (PRNP), which is responsible for making the prion protein PrPC. This exists in your brain and helps regulate body functions, such as sleep.

The Cleveland Clinic uses an example of folding laundry to demonstrate the significance of the PRNP gene.

"When there’s a mutation on the PRNP gene, the amino acids that build the PrPC proteins don’t have instructions to build the proteins correctly. This mutation is similar to folding your laundry," the site says.

"If you’re unsure how to fold a t-shirt, you might ball up the fabric and put it in a drawer. Over time, that drawer progressively becomes difficult to close because you collect several t-shirts that aren’t folded correctly.

"Misfolded t-shirts are PrPC proteins that collect on your brain and become toxic to the cells in your nervous system, which creates symptoms."

FFI can be inherited and only one parent needs to pass the affected gene on for their child to inherit the condition. Rare cases of FFI where there is no history of the condition in a family do occur.

If you have FFI, you can potentially pass the mutation onto your own children.

What are the symptoms of fatal familial insomnia?

The three main symptoms of FFI are insomnia or difficulty sleeping, memory loss and muscle twitching or jerking. The disorder is degenerative, meaning symptoms continue to worsen over time.

There are several symptoms to look out for (Getty Stock Images)

Nervous system overactivity, such as high blood pressure, anxiety and an unusually fast heart rate is also a symptom of FFI, as well as suffering from hallucinations or seeing things that aren't there.

Weight loss and mental health changes are also changes to look out for.

Symptoms typically begin between the ages of 20 and 70, with the average age to begin experiencing symptoms being 40 years old. Early symptoms may seem similar to those of dementia or Alzheimer's disease.

Can fatal familial insomnia be treated?

Symptoms of FFI are life-threatening and there is currently no cure for the condition. Studies for suitable treatment options to reduce the progression of symptoms and extend the life expectancy of people with the condition are ongoing, according to Cleveland Clinic.

Death from FFI occurs due to damage to the brain and nervous system, leading to mental deterioration and insomnia.

Life expectancy can range from a few months to a couple of years, with treatment likely to focus on palliative care.