Another common feature of KLS, seen in about 60 to 70 percent of cases, is a ravenous appetite for sweets, potato chips, and other high-calorie comfort foods. A similar percentage of patients may also engage in inappropriate sexual behavior during episodes. During one of his first bouts of KLS, Maier recalls being dragged out to watch a basketball game, where he began groping his girlfriend directly in front of his parents and her parents. “I think the hypersexuality just comes down to the fact that you’re less inhibited in this fuzzy state of mind,” says Maier. “If it feels good, you just want to do it, regardless of the consequences.”
“Stimulants can make KLS patients less sleepy, but they’re still in this weird fog and can become agitated or aggressive. Many doctors just want to act, but the best course of action may be to do nothing.”
Just what causes KLS is unknown. Brain activity during a bout of hypersomnia is very different from that of someone in a coma or vegetative state, who typically exhibits severe EEG abnormalities. When wired up with electrodes at a sleep clinic, a person with KLS has the same sleep phases as a healthy person, says Mignot, “only they keep cycling on and on through the different stages of sleep,” rather than exiting the cycle and waking up. One hint about the disease’s underlying cause comes from functional magnetic resonance imaging (fMRI) studies, which capture pictures of the brain at work. In one study conducted in Taiwan, the researchers uncovered abnormal activity in the hypothalamus and thalamus—parts of the brain that play a critical role in regulating sleep, eating, and sex. “Sometimes changes were also seen in the cortex of these patients, which may explain some of the cognitive impairment,” says Mignot.
Heredity may play a role. A questionnaire sent to 100 patients and their parents revealed that KLS disproportionately affects Ashkenazi Jews. Given that the disease is frequently preceded by fever and other flulike symptoms, it seems that a combination of factors precipitates the illness. “My leading hypothesis,” says Mignot, “is that KLS is caused by a virus or bacterium that some individuals are more genetically susceptible to.”
Exploiting methods that he developed in his hunt for the gene responsible for narcolepsy, Mignot is now in hot pursuit of a KLS gene. He’s identified several families with a strong hereditary pattern of the disease and has begun searching for common genetic markers. At the same time, the KLS Foundation is working with laboratories to collect blood samples from KLS patients and their families for a genetic study, and nasal swabs from patients during active episodes with the aim of isolating an infectious trigger. “We’re very encouraged that we will soon have some answers to an illness that has heretofore been a complete mystery,” says Neal Farber, father of a son and a daughter with KLS and co-president of the foundation.
For now, medicine has little to offer sufferers. “Stimulants can make KLS patients less sleepy, but they’re still in this weird fog and can become agitated or aggressive,” says Mignot. “That can be worse than simply sleeping.” Other treatments that have been tried with marginal or no benefit are lithium, antidepressants, anticonvulsants, and mood stabilizers. “Many doctors just want to act,” says Mignot, “but the best course of action may be to do nothing.”
No magic kiss from a handsome prince (or princess) will awaken sufferers from their long slumber. But in keeping with its fairy-tale symptoms, KLS does have a happy ending: Virtually everyone outgrows it.
