Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness (EDS) and difficulty maintaining both sleep and wakefulness.   The International Classification of Sleep Disorders, third edition (ICSD-3), divides narcolepsy into two subtypes, narcolepsy type 1 and narcolepsy type 2.

Narcolepsy type 1 is caused by a hypocretin (orexin) deficiency, and definitive diagnosis is based on the presence of cataplexy (sudden episodes of muscle weakness triggered by strong emotions) or a hypocretin deficiency confirmed through laboratory testing (although this testing is not always available). The pathophysiology for narcolepsy type 2 is uncertain, and it can be diagnosed by clinical history and sleep studies.

Because of the strong association between narcolepsy and the presence of the HLA-DQB1*06:02 allele, genetic testing for HLA-DQB1*06:02 can help rule out narcolepsy.

Tabs Content
Content Review: 
October 2019

Last Update: October 2019