<unk>  (KLS) also known as "Sleeping Beauty syndrome" is a rare sleep disorder characterized by persistent episodic hypersomnia and cognitive or mood changes. Many patients also experience hyperphagia, hypersexuality and other symptoms. Patients generally experience recurrent episodes of the condition for more than a decade. Individual episodes generally last more than a week but less than a month. The condition greatly affects the personal, professional, and social lives of sufferers, but symptoms spontaneously resolve and seldom cause permanent issues. The severity of symptoms and the course of the disease vary between sufferers. Patients commonly have about 20 episodes over about a decade. Several months generally elapse between episodes. The onset of the condition usually follows a viral infection; several different viruses have been observed to trigger KLS. It is generally only diagnosed after similar conditions have been excluded; MRI, CT scans, lumbar puncture, and toxicology tests are used to rule out other possibilities. The disease's mechanism is not known, but the thalamus is thought to possibly play a role. Tomography has shown hypoperfusion in the brains of patients during episodes.
KLS is very rare, occurring at a rate of one in a million, which limits research into genetic factors. The condition primarily affects adolescent males, although some patients are female and the age of onset varies. There is no known cure, and there is little evidence supporting drug treatment. Lithium has been reported to have limited effects in case reports, decreasing the length of episodes and duration between them in some patients. Stimulants have been shown to promote wakefulness during episodes, but they do not counteract cognitive symptoms or decrease the duration of episodes. The condition is named after Will<unk>  and Max<unk> , who described cases of the disease in the early 20th century. It was added to the International Classification of Sleep Disorders in 1990.
Kleine–Levin syndrome
Kleine-Levin syndrome
Weaver syndrome
Benedikt's syndrome
Urban-Rogers-Meyer syndrome
Clark-Baraitser syndrome
Allain Babin Demarquez syndrome
Jadassohn-Lewandowsky syndrome