Nishino · Lancet (London, England) 2000 · case series · n=9

Hypocretin (orexin) deficiency in human narcolepsy.

Cited 1788 times in the scientific literature.

Level 4 - case-series / case-control

Small case series measuring hypocretin in humans with narcolepsy.

PubMed 10615891 · doi:10.1016/S0140-6736(99)05582-8 · record verified 2026-08-26

What was done

Hypocretin levels were evaluated in nine individuals with narcolepsy following earlier animal model findings involving hypocretin system genes.

What was found

Hypocretin was undetectable in 7 out of 9 people with narcolepsy.

Why it matters

It provides early human evidence directly linking hypocretin deficiency to narcolepsy pathophysiology.

Limits

The sample size is extremely small (n = 9). The abstract does not mention a control group, assay methodology, the biological tissue or fluid assayed, or reasons why two individuals had detectable hypocretin.

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