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Canine Mendelian disease record

Narcolepsy (Discovered in the Labrador Retriever)

Narcolepsy (Discovered in the Labrador Retriever). Autosomal recessive. Observed in 4 of 266 breeds tested in the Sniff Atlas, with measured carrier frequencies drawn from 242,665 dogs (Donner 2023). Per-dog phenotype outcome depends on penetrance, modifiers, and environment; the carrier frequencies below describe variant prevalence, not disease incidence.

OMIA identifier
OMIA:000703-9615
Autosomal recessive
Source dataset
Sniff Atlas v1.0.1 / DOI
The human connection

A model of human narcolepsy 1

Dogs with this condition carry a change in HCRTR2. In people, changes in the same gene cause narcolepsy 1. That makes affected dogs a naturally-occurring model of the human disease, and it is part of why studying dogs moves medicine forward for everyone. It does not mean your dog has the human disease. It means the two share an underlying biology.

In people, the disease is described as: A rare disorder characterized by sudden and transient episodes of loss of muscle tone. It often follows an experience of intense emotions. It is seen in patients with narcolepsy.

In humans it is also called: NRCLP1, HCRT narcolepsy, narcolepsy caused by mutation in HCRT.

MONDO:0008062 OMIM 161400

Mapped from OMIA via the human disease's OMIM entry to the Mondo Disease Ontology (Monarch Initiative, CC-BY 4.0). Sniff renders this as a model-of link; the canine disease remains the subject of this page.

About this disease

From OMIA's curated record

Documented in OMIA (Online Mendelian Inheritance in Animals). This describes the disease as recorded in the published literature, not a prediction for any individual dog. As of 2026-06-03.

Summary

Narcolepsy is a sleep disorder characterized by shortened sleep latency and cataplexy. Genetic tests are available to detect the causative mutations in HCRTR2.

Clinical features

Dogs with familial narcolepsy may show signs between 4 weeks to 6 months of age. Affected dogss are sleepy, and cannot maintain long stretches of wakefulness. Affected dogs fall asleep faster than normal dogs. Narcolepsy is neither progressive nor life-threatening (Tonokura et al., 2007). In response a positive emotional stimulus (such as food or play) affected animals experience cataplexy, which is a sudden loss of muscle tone without loss of consciousness (Tonokura et al., 2007). During an attack of cataplexy, common first signs are buckling of both hindlimbs and drooping of the neck. The dog then collapses and is still for a period of seconds to minutes. The muscles are always flaccid during attacks. Dogs usually remain conscious and open-eyed during attacks, and are capable of following objects with their eyes. If an attack lasts for longer than a couple of minutes, the dog may fall asleep. Cataplexy can often be treated with tricyclic antidepressants such as imipramine or clomipramine (Tonokura et al., 2007). Prazosin and physostigmine increase cataplexy in narcoleptic dogs and lower hypocretin levels in normal dogs. Methamphetamine, labetalol, and phenylephrine decrease cataplexy in narcoleptic dogs and raise hypocretin levels in normal dogs (Wu et al., 2011).

Molecular genetics

Armed with the mapping knowledge summarised in the Genetic mapping section above, Lin et al. (1999) performed a Herculean series of linkage and comparative physical mapping studies within a 1.8Mb region of chromosome CFA12, finally narrowed the chase down to one comparative positional candidate gene, namely HCRTR2, which "encodes a G protein–coupled receptor with high affinity for the hypocretin neuropeptides". They then reported that a "SINE insertion mutation [in the HCRTR2 gene, omia.variant:419] is the cause of narcolepsy in Dobermans". These same authors showed that the causative mutation in Labrador retrievers is a deletion of exon 6 due to a "G to A transition in the 5′ splice junction consensus sequence (position +5, exon 6–intron 6)" (omia.variant:368). The work of Lin et al. (1999) was the subject of a commentary by Reilly (1999). The causative mutation in dachshunds is a G to A substitution at exon 1 (omia.variant:64) of the HCRTR2 gene (Hungs et al., 2001).
Mondino et al. (2025) report a novel tandem duplication in HCRTR2 in affected Dogo Argentino dogs (omia.variant:1784).

Pathology

In normal dogs, hypocretin activity is reinforced by a positive feedback mechanism mediated by hypocretin-2 receptors, which is crucial to normal regulation of sleep and wakefulness (Wu et al., 2011). While affected dogs lack functional HCRTR2, they have normal hypocretin-1 receptors, normal CSF hypocretin levels, and normal numbers of hypocretin neurons (Wu et al., 2011).

Inheritance

The disorder shows classic autosomal recessive inheritance (Foutz et al., 1979).

Control

Relatives of affected dogs should be tested. Breeding of affected dogs or carriers is not recommended.

Genetic testing

There are tests available to detect the causative mutations in the dachshunds, Labrador retriever, and Doberman pinscher.

Human analog

OMIA links this condition to its human counterpart in OMIM (Mendelian Inheritance in Man), the place to read across to the deeper human literature for the same biology.

Disease · OMIM 161400 Gene · OMIM 602393

Source: OMIA (Nicholas, Tammen & the Sydney Informatics Hub), entry OMIA:000703-9615, doi:10.25910/2AMR-PV70 (CC-BY 4.0).

The evidence

Published references

The peer-reviewed papers behind this disease, curated by OMIA. Starred entries are OMIA-designated landmark papers. Showing 6 of 75.

  5. Sleep disorders in dogs: A pathophysiological and clinical review. · Top Companion Anim Med · 2021 · PMID 33556640
  6. Animal models of sleep disorders. · Comp Med · 2013 · PMID 23582416

References curated by OMIA (Nicholas, Tammen & the Sydney Informatics Hub), doi:10.25910/2AMR-PV70 (CC-BY 4.0). Full list at the OMIA entry.

Predict a litter

Set each parent's status for Narcolepsy (Discovered in the Labrador Retriever) and see the odds for their puppies. Single recessive variant, exact Mendelian math.

Parent A
Parent B
NNClear
NmCarrier
NmCarrier
mmAffected
Clear25%
Carrier50%
Affected25%

These are the genetic odds for one known variant, not a promise: a real litter varies around them, and penetrance or other genes can change whether the condition ever appears. Use it to avoid pairing two carriers and to keep a line healthy, not to engineer a dog. Inheritance mode per OMIA.
Your breed

See what Narcolepsy (Discovered in the Labrador Retriever) looks like in your dog's breed.
Carrier frequency by breed

Top 4 well-sampled breeds (n ≥ 50)

Maximum per breed across variants in the Donner 2023 cohort, with . The list below is split into well-sampled breeds (n ≥ 50 tested) and small-sample breeds (n < 50, where the Wilson CI typically spans more than 20 percentage points and frequencies should not be compared directly to the well-sampled entries). Frequencies are population-level, not per-litter or per-line.

0%1%2%
Labrador Retriever<0.1% · n 16,856
Schnauzer Miniature<0.1% · n 4,638
Rottweiler<0.1% · n 4,718
American Staffordshire Terrier<0.1% · n 42,793
n = 69,005 dogs · Donner et al. 2023 carrier-screening cohort · Sniff Atlas
Each bar is one well-sampled breed; the whisker is its Wilson 95% CI, and fainter bars have wider intervals. Frequencies are population-level, not per-litter. Carrier status for Narcolepsy (Discovered in the Labrador Retriever) is measured; phenotype outcome depends on penetrance and modifiers.
▸ Full table with Wilson 95% confidence intervals
Breed Carrier frequency n tested
Labrador Retriever <0.1% 16,856
Schnauzer Miniature <0.1% 4,638
Rottweiler <0.1% 4,718
American Staffordshire Terrier <0.1% 42,793

262 additional breeds in the Donner 2023 cohort were tested but showed no carriers.

Scope of this record

Scope

This record carries the breed-level carrier frequencies from the Donner 2023 cohort. Penetrance data (the fraction of at-risk dogs that develop the phenotype) is not yet quantified for this disease in the Sniff Atlas v1.0.1. The OMIA entry is the authoritative reference for the clinical phenotype, inheritance pattern, and gene assignment.

Predicted disease relevance at the per-dog level is UNPROVEN. The carrier frequency is measured; phenotype outcome depends on penetrance, environment, and modifier loci. Consult a veterinarian for clinical interpretation.

How to cite this record

Citations

If you use this record in published work, cite the Sniff Atlas (the published dataset that carries the breed-level carrier frequencies) and the upstream sources:

  • Sniff Atlas v1.0.1 for the per-breed carrier frequencies:

    Gehring, M. (2026). Sniff Atlas v1.0.1. Zenodo. https://doi.org/10.5281/zenodo.20566358. CC-BY 4.0.

  • OMIA for the disease definition, inheritance, and gene assignment:

    Nicholas, F. W., & Tammen, I. (2024). OMIA. Sydney Informatics Hub, The University of Sydney. https://doi.org/10.25910/2AMR-PV70. Entry: OMIA:000703-9615.

  • Donner et al. 2023 for the breed × variant carrier-frequency cohort:

    Donner, J., Freyer, J., Davison, S., Anderson, H., Blades, M., Honkanen, L., et al. (2023). Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs. PLOS Genetics, 19(2), e1010651. https://doi.org/10.1371/journal.pgen.1010651.

Full citation formats (BibTeX, RIS, CITATION.cff) at sniff.world/cite.

Related

Related

Last updated
Sources: Sniff Atlas v1.0.1 · OMIA OMIA:000703-9615 · Donner et al. 2023