A prepro-orexin gene polymorphism is associated with narcolepsy.

The orexin (hypocretin) neurotransmitter system was recently shown to be directly involved in the pathogenesis of narcolepsy in two animal models. Furthermore, decreased levels of orexin A in the CSF were shown in narcoleptic patients. To define any genetic contribution of orexin to the etiology of narcolepsy, the authors screened the entire prepro-orexin gene for mutations or polymorphisms in 133 patients suffering from narcolepsy. They report an association of a rare polymorphism in the prepro-orexin gene with narcolepsy in a cohort of 178 patients.