Undetectable levels of CSF hypocretin-1 (orexin-A) in two prepubertal boys with narcolepsy.

We report on two prepubertal narcoleptic boys with undetectable levels of hypocretin-1 (orexin-A) in their cerebrospinal fluid (CSF). The disease onset times were 6 and 8 years, and CSF was collected 8 and 20 months after the onset, respectively. The initial symptoms were excessive daytime sleepiness, cataplexy and disrupted nocturnal sleep. Both subjects are DRB1*1501 and DQB1*0602 positive. The measurement of CSF hypocretin-1 is valuable for the decisive diagnosis of narcolepsy and for selecting the type of treatment in prepubertal children. Our results suggest that a significant degree of hypocretin deficiency is already present at the disease onset.