Records show that, throughout the 18th, 19th and 20th centuries, deaths consistent with FFI ran through the generations of the Patient Zero family.
In the 1980s, a descendant of the family named Silvano suddenly began showing symptoms of the disease. A handsome, vibrant playboy, he had lived in the shadow of this potential killer all his life.
"Silvano, I think, in his heart, knew that he was going to get the disease, and one day, he woke up , and his pupils were as small as pinpricks, and he began to sweat," said Max. "And he decided that he would not die without the family learning something, some shred of evidence about what had been killing them for generation after generation."
Silvano and other family members were filmed at the University of Bologna's sleep clinic. On the tape, Silvano looks as if he's sleepwalking. But he was really in a permanent state of pre-sleep behavior. And often, you will see him and other patients making gestures, like combing their hair or washing their hands or handling objects.
According to Dr. Elio Lugaresi, director of the sleep clinic, Silvano and the others were unable to drop into a deep REM sleep, and sleep medications only accelerated their restless descent toward death.
"We gave intravenous doses of barbiturates [in an] attempt to help the patient sleep," said Lugaresi. "The result was that they went from this pre-sleep, nonsleep, to deep coma without ever passing to a sleep stage."
Just before his death, Silvano made a remarkable and selfless offer, bequething his brain to researchers, which finally opened a window into the mystery of FFI.
Microscopic views showed that healthy proteins misfolded, triggered by genetic mutations, creating what doctors call prions. These abnormal proteins build up in the brain, forming clumps that destroy nerve cells, eventually leaving spongelike holes in the brain. Mad cow disease is also a prion disease.
"In fatal familial insomnia, most of the damage, and where the prions are accumulating, seems to be in an area of the brain called the thalamus," explained Dr. Michael Geschwind, who studies FFI at the University of California at San Francisco.
"The accumulation of the prion in the brain leads to nerve cell injury, and eventually, to nerve cell death."
Geschwind said the thalamus is the region of the brain responsible for the regulation of sleep. For reasons still not fully understood, symptoms of FFI don't show up until midlife, after child-bearing years.
Each child has a 50-50 chance of receiving the killer gene, so the disease has been unwittingly passed through generations, which brings us back to sisters Carolyn and Cheryl.
Given the opportunity to take a simple blood test to determine if they had inherited the disease, Cheryl said no. "For me, I look at it as, I can go, and they can tell me that either I do have this or I don't have this, and I can die in a car accident on the way home. I may just as easily die from cancer, or ... anything," she said.
"We all have a terminal something. If we live long enough, we're going to die from something. That's the way it goes."