NEW YORK - Dani Farber had a completely normal childhood.
"Loved to play sports, did very well in school, hung with my friends," he said.
But he remembers when things suddenly changed.
"One day when I was 15, I woke up suddenly and I was sick." Farber, now 40, said. "I was bedridden for weeks and, on some occasions, for months on end. When I was in these episodes, my life completely stopped."
Farber said he would sleep around the clock, 22 to 23 hours a day. When he was awake, he had no energy to get up for food or water. He said he didn't even look like himself.
That first episode lasted a week and a half but was soon followed by a second one and then another.
"It was terrifying," Farber said.
Most of all because no one could figure out what was causing the sleeping spells. He underwent blood tests, spinal taps, MRIs and sleep studies, but everything came back normal. Frustration built.
"It was very obvious to me and my family that something very scary and something very serious was going on," he said.
Finally, a doctor in the Boston area, where Farber lived, came up with a diagnosis: Kleine Levin syndrome. In the media, it's often called "sleeping beauty syndrome."
"It's a true misnomer. There's nothing beautiful about KLS," Jennifer Grossman said. "It's a beast, it's a beast of a disease."
A beast that Grossman's family is currently facing down. Her 17-year-old son Cooper has a story much like Farber's.
"He's an amazing young, kind, polite, happy, healthy, energetic kid," she said of Cooper.
But at 15, during his freshman year, his first episode struck.
"Lethargy turned into almost like a coma, his pupils were extremely dilated, his skin color became very pale, it was impossible for him to stay awake," Grossman recalled.
According to the KLS Foundation, on which both Grossman and Farber are board members, it takes an average of four years for someone to get a diagnosis of Kleine-Levin Syndrome.
"It was incredibly frustrating," Grossman said of the road to diagnosis.
"Every person that we met with basically said, there's nothing wrong, and one doctor told me to pray, that was basically what she said, to pray for my child." After countless doctors and tests, and still no answers, a family member's Google search turned up articles on KLS.
The Grossmans, who live in Livingston, New Jersey, booked the first appointment they could get with Dr. Orrin Devinsky.
"This is very much a medical mystery," Devinsky said at his office at NYU, where he is a professor of neurology and epilepsy.
Devnisky estimates he has treated as many as 75 KLS patients over the course of his career.
"To date, we really don't know why it afflicts one person and not another," he said.
"During an episode, essentially the sleep system is turned on and the wakefulness is turned off, and those are regulated and very deep, primitive ancient areas of our brain," Devinsky added. "We think it's some abnormality in that ancient part of the brain, possibly an auto-immune, possibly virus, possibly neurochemical, the exact cause and mechanisms are still something we are working on."
Many patients have a flu-like virus, or infection before the onset of KLS, though Devinsky said that's not necessarily a cause.
Doctors at Stanford are looking at whether KLS may have genetic tendencies. One reason for that is Dani Farber, because just two years after his diagnosis, his younger sister Ariel began having episodes too.
"Collectively, my sister and I had 40 episodes over a 10 year period," he said. "It robbed both of us of large chunks of our teenage years which are some pretty transformative years, and it took a big toll on our families."
The Farbers were the first documented siblings to have KLS, but the list has since grown.
"I do think genetic factors contribute," Devinsky said. "But they're not the major ones that seem to be driving it."
KLS affects just 1 to 2 in 1 million people.
Because of its rarity, research and funding have lagged, though that's something Grossman and the KLS foundation are fighting hard to change.
"Right now, there's no known cause or cure," Grossman said. "However there will be one, and I know there's one out there."
Cooper has now had six episodes over three years, missing about 70 days of high school, at a time when he should be focused on academics and applying to college.
Grossman said her family lives in fear of when the next episode will strike.
"Every day is like Russian roulette," she said.
There is one silver lining of KLS. and that's that it's finite. Most patients stop having episodes by age 30.
"Knowing he can outgrow it is fantastic, and that's what keeps me going, but when will that be? It's a magic question, it's a mystery, and I just don't know when it's going to be," she said.