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10 sources retrieved · Most recent: April 2026 · Index updated 15 days ago
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HCRTR2
hypocretin receptor 2
Chromosome 6 · 6p12.1
NCBI Gene: 3062Ensembl: ENSG00000137252.10HGNC: HGNC:4849UniProt: O43614
84PubMed Papers
20Diseases
9Drugs
0Pathogenic Variants
FUNCTIONAL ROLE
Receptor
CLINICAL
FDA Approved Target
DATA QUALITY
✓ Experimental GO Evidence✓ Swiss-Prot Reviewed
orexin receptor activityneuropeptide signaling pathwayprotein bindingregulation of cytosolic calcium ion concentrationinsomniaAbnormality of the skeletal systemgouthyperuricemia
✦AI Summary

HCRTR2 (hypocretin receptor 2) is a G-protein coupled receptor that binds the neuropeptides orexin-A and orexin-B, coupling with both Gq/11 and Gi/o heterotrimeric G-proteins to initiate downstream signaling cascades 1. The receptor plays a critical role in sleep-wake regulation, with HCRTR2 being strongly linked to sleep-wake control compared to HCRTR1 which is more associated with motivation and reward functions 1. Loss of orexin-producing neurons leads to narcolepsy, and OX2R knockout mice display clear narcolepsy-like phenotypes including fragmented sleep-wake cycles 2. The receptor is expressed in the hypothalamus and its activation increases wakefulness, as demonstrated by selective HCRTR2 agonists that promote wake states in wild-type but not OX2R knockout mice 2. HCRTR2 genetic variants have been investigated in cluster headache, a severe neurovascular disorder with circadian patterns, though results across populations have been inconsistent 345. The receptor system represents a therapeutic target, with HCRTR2 antagonists approved for insomnia treatment and agonists showing potential for treating excessive daytime sleepiness 1. Additionally, HCRTR2 variants have been associated with daytime napping behavior in genome-wide studies 6.

Sources cited
1
HCRTR2 is a GPCR that binds orexin peptides and is strongly linked to sleep-wake control, with antagonists approved for insomnia treatment
PMID: 34052813
2
OX2R knockout mice show narcolepsy-like phenotypes and selective OX2R agonists increase wakefulness in wild-type but not knockout mice
PMID: 31654653
3
HCRTR2 genetic variants have been investigated in cluster headache with inconsistent results across populations
PMID: 30652302
4
Analysis of HCRTR2 polymorphisms in cluster headache showed no significant association in Southeastern European population
PMID: 31768945
5
Haplotype analysis confirmed association between HCRTR2 gene and cluster headache in some populations
PMID: 18399985
6
HCRTR2 variants were identified in genome-wide association study of daytime napping behavior
PMID: 33568662
Disease Associationsⓘ20
insomniaOpen Targets
0.60Moderate
Abnormality of the skeletal systemOpen Targets
0.44Moderate
goutOpen Targets
0.39Weak
hyperuricemiaOpen Targets
0.38Weak
major depressive disorderOpen Targets
0.37Weak
circadian rhythmOpen Targets
0.36Weak
Sleep DisorderOpen Targets
0.36Weak
sleepOpen Targets
0.33Weak
Alzheimer diseaseOpen Targets
0.31Weak
placental retentionOpen Targets
0.31Weak
alcohol dependenceOpen Targets
0.29Weak
deliriumOpen Targets
0.28Weak
muscular atrophyOpen Targets
0.26Weak
epilepsyOpen Targets
0.26Weak
dislocationOpen Targets
0.26Weak
ovarian dysfunctionOpen Targets
0.20Weak
narcolepsy-cataplexy syndromeOpen Targets
0.11Weak
post-traumatic stress disorderOpen Targets
0.10Weak
opioid use disorderOpen Targets
0.10Weak
diabetic neuropathyOpen Targets
0.09Suggestive
Pathogenic Variants
No pathogenic variants reported on ClinVar for this gene.
View on ClinVar ↗
Drug Targets9
ALMOREXANTPhase III
Orexin receptor antagonist
insomnia
DARIDOREXANTApproved
Orexin receptor 2 antagonist
insomnia
DARIDOREXANT HYDROCHLORIDEApproved
Orexin receptor 2 antagonist
insomnia
FILOREXANTPhase II
Orexin receptor antagonist
diabetic neuropathy
LEMBOREXANTApproved
Orexin receptor 1 antagonist
insomnia
ORN-0829 HYDRATEPhase III
Orexin receptor antagonist
insomnia
SB-649868Phase II
Orexin receptor 1 antagonist
insomnia
SELTOREXANTPhase III
Orexin receptor 2 antagonist
major depressive disorder
SUVOREXANTApproved
Orexin receptor antagonist
insomnia
Related Genes
GNB1Protein interaction100%GNAI1Protein interaction100%GNASProtein interaction100%POMCProtein interaction93%HCRTR1Protein interaction77%HCRTProtein interaction67%
Tissue Expression6 tissues
Heart
100%
Ovary
100%
Brain
88%
Bone Marrow
25%
Lung
25%
Liver
0%
Gene Interaction Network
Click a node to explore
HCRTR2GNB1GNAI1GNASPOMCHCRTR1HCRT
PROTEIN STRUCTURE
Preparing viewer…
PDB5WQC · 1.96 Å · X-ray
View on RCSB ↗
Constraintⓘ
LOEUFⓘ
0.60LoF Tolerant
pLIⓘ
0.53Intermediate
Observed/Expected LoF0.39 [0.26–0.60]
RankingsWhere HCRTR2 stands among ~20K protein-coding genes
  • #5,668of 20,598
    Most Researched84
  • #423of 1,025
    FDA-Approved Drug Targets4
  • #4,109of 17,882
    Most Constrained (LOEUF)0.60 · top quartile
Genes detectedHCRTR2
Sources retrieved10 papers
Response time—
📄 Sources
10▼
1
Hypocretin/Orexin Receptor Pharmacology and Sleep Phases.
PMID: 34052813
Front Neurol Neurosci · 2021
1.00
2
Analysis of HCRTR2 Gene Variants and Cluster Headache in Sweden.
PMID: 30652302
Headache · 2019
0.90
3
Genetic determinants of daytime napping and effects on cardiometabolic health.
PMID: 33568662
Nat Commun · 2021
0.80
4
A genome-wide scan and HCRTR2 candidate gene analysis in a European cluster headache cohort.
PMID: 16801656
Neurology · 2006
0.70
5
Analysis of HCRTR2, GNB3, and ADH4 Gene Polymorphisms in a Southeastern European Caucasian Cluster Headache Population.
PMID: 31768945
J Mol Neurosci · 2020
0.60