What happens when you really can't sleep — ever.

Stress, deadlines, or caffeine can give people a few sleepless nights, but there are some people for whom insomnia is chronic, complete, and fatal. Find out about a rare, but scary, condition known as fatal familial insomnia.

The first case of fatal familial insomnia shocked the world in 1984. An Italian man named Silvano, in his mid-fifties, with no history of major sleep problems, checked into a prominent sleep clinic. He had completely lost his ability to sleep. For most of us, having 'insomnia' means not being able to sleep for a couple of hours when going to bed. Sufferers of FFI are unable to sleep at all, sometimes for months. The man whose arrival at that clinic in Bologna first brought the condition to the world's attention, died after four months of documented insomnia. Then, and now, doctors have no explanation for his death.

Silvano's family, and about forty other families world-wide, have a specific genetic mutation. Almost all members of affected families have reported a full night without sleep, but the disease only kicks into gear in some cases. In some cases, though, the insomnia becomes chronic and life-threatening.

The 1984 official diagnosis was preceded by a stream of unofficial deaths. In the 1970s Silvano's niece suddenly began to lose the ability to sleep, and died about a year after the onset of the illness. Sleeping pills and other forms of medication did no good. Some time after she died, her sister was struck with the same set of symptoms. The woman's husband was a doctor. Mystified and frightened, he looked back through ancient family records and found more family members who had died of 'epilepsy' or 'mental illness,' that seemed to fit the pattern, and met older and more distant relatives who had seen their family members die of a similar affliction.

Genetic testing revealed that fifty percent of the family were carriers of the gene. Most of the carriers remained healthy throughout their lives. Those that lost the ability to sleep, though, faced a horrific future. The insomnia was caused by a protein that began attacking the structure of the brain. Silvano's brain, when examined by doctors, was full of tiny holes. Once the sleeplessness has gone on for too long, the patient becomes suspended in a half-dream-reality. Patients act out their dreams, and mime combing their hair or putting on clothes. They are still awake, but unable to engage with things happening around them. They lose the ability to walk and talk as their bodies become weaker. At last, after months of sleeplessness, they die.

Doctors still don't know exactly why those patients were affected when other carriers of the gene were not. In fact, doctors don't know exactly why people sleep, or why the loss of the ability to sleep becomes fatal. They hope that a cure for this rare disease will come in the next decade, but right now, the only hope for those with the mutation is that it never becomes active.

Image: Art Institute of Chicago

Via MSNBC and ABC.