We've all had nights where we struggle to fall asleep, but imagine being trapped in a cycle of insomnia that gets progressively worse until you cannot get a single second of shuteye – and then, you die.

That is exactly what happened to Silvano, an Italian man described as having firecracker red hair and an impeccable dress sense. In 1984, Silvano was holidaying aboard a cruise ship when he noticed a strange assortment of symptoms, starting with a severe case of the sweats and pupils that had shriveled to the size of pinpricks. The illness worsened. He couldn't sleep, he developed tremors, and he was dead within months.

This is fatal familial insomnia (FFI) – an extremely rare and extremely harrowing condition that is, in almost all cases, passed down the generations by a faulty gene. There have been just 24 reported cases of what is called sporadic FFI, which is when a gene spontaneously mutates in a person who otherwise has no family history of the illness.

Journalist DT Max describes the onset of FFI in his 2006 book The Family That Couldn’t Sleep:

Typically, one day in middle age, the sufferer finds that he [or she] has begun to sweat. A look in the mirror will show that his pupils have shrunk to pinpricks and he is holding his head in an odd, stiff way…Constipation is common, the women suddenly enter menopause and the men become impotent. The sufferer begins to have trouble sleeping and tries compensating with a nap in the afternoon, but to now avail. His blood pressure and pulse have become elevated and his body is in overdrive. Over the ensuing months, he tries desperately to sleep, sometimes closing his eyes but never succeeding in falling into more than a light stupor.

There can be other signs – think panic attacks, weight loss, phobias, and a loss of appetite. The condition progresses quickly and the individual may begin to experience hallucinations, delirium, and uncoordinated movements or twitches. What starts as brain fog turns into confusion and finally into difficulty walking and talking.

What's more, it is lethal. The sufferer is usually dead within 12 to 18 months of noticing the first symptoms.

In Silvano’s story, the gene mutation could be traced back to a doctor living in late-18th century Venice. The doctor's nephew, an Italian aristocrat called Giuseppe, also fell ill. Then, his sons, Angelo and Vincenzo, and so on down the bloodline until it reached Silvano in the 1980s. 

There are at least 28 families around the world inflicted with the gene. Most, like Silvano's, have a tragic history involving an unknown but deadly disease that strikes in middle age.

Much of what we now know about FFI is thanks to Silvano himself, who booked an appointment with scientists at the University of Bologna, Italy, at the request of his daughter and son-in-law after he began to experience symptoms. Since then, the university has completed genetic tests and studies on several members of the family. However, each has chosen to remain unaware of whether or not they possess the FFI gene. 

Researchers at Bologna discovered the condition is the result of a deformed brain protein called a prion, much like Creutzfeldt-Jakob disease and bovine spongiform encephalopathy (better known as mad cow disease). The particular prion associated with FFI affects an area of the brain called the thalamus, which is responsible for managing the sleep-wake cycle and is involved in other important brain activities, such as balance, memory, speech, personality, emotions, and general interbrain communication.

The mutation causes the neurons in the thalamus to break down and it is this lack of neurons that triggers the symptoms of FFI. 

It is also what stops the body from being able to achieve sleep mode. In a healthy person, the blood pressure drops just before falling asleep, but in someone with FFI, it does not. Instead, the body remains on high alert and is unable to reach a deep and restorative slumber. 

Most people with the defected gene will start to experience symptoms between the ages of 32 and 62, but there have been incidents of it happening as young as 12 and as old as 84. It is a dominant gene mutation, which means a child whose parent has the condition has a 50 percent chance of developing it themselves. 

You might now be wondering if there is a cure – sadly, there is not, but there are various treatments in the pipeline and methods that may delay symptoms. One patient, known only as Daniel, was able to postpone the more severe symptoms and death with an array of techniques, including a sensory deprivation tank that allowed him to sleep for hours at a time. Combined, the treatments were so effective at alleviating his symptoms that Daniel was able to spend his final years writing a book and traveling around the US in a motorhome.

Then there is Sonia Vallabh, who lost her mother to the condition in 2010. Finding out that she too shared the gene, Vallabh and her husband, Eric Minikel, gave up their jobs, became scientists, and embarked on a PhD at Harvard Medical School. They now study prion diseases in the Schreiber Lab at Board Institute, where their goal is to find a cure before Vallabh starts to develop symptoms herself. They keep regular updates on their progress at prionalliance.org.

The couple remains optimistic.