OPRM1
Chr 6opioid receptor mu 1
Also known as: LMOR, M-OR-1, MOP, MOR, MOR1, OPRM
This gene encodes one of at least three opioid receptors in humans; the mu opioid receptor (MOR). The MOR is the principal target of endogenous opioid peptides and opioid analgesic agents such as beta-endorphin and enkephalins. The MOR also has an important role in dependence to other drugs of abuse, such as nicotine, cocaine, and alcohol via its modulation of the dopamine system. The NM_001008503.2:c.118A>G allele has been associated with opioid and alcohol addiction and variations in pain sensitivity but evidence for it having a causal role is conflicting. Multiple transcript variants encoding different isoforms have been found for this gene. Though the canonical MOR belongs to the superfamily of 7-transmembrane-spanning G-protein-coupled receptors some isoforms of this gene have only 6 transmembrane domains. [provided by RefSeq, Oct 2013]
Some data sources returned errors (1)
omim: Error: OMIM fetch failed: 429
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Tolerant to missense variation
This gene — mechanism propensity
This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). Both the Badonyi & Marsh prediction and the broader genomic evidence point to gain-of-function as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.
Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
108 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 0 | 0 | 0 | 0 | 0 |
Likely Pathogenic | 0 | 0 | 0 | 0 | 0 |
VUS | 0 | 83 | 0 | 0 | 83 |
Likely Benign | 0 | 8 | 0 | 4 | 12 |
Benign | 1 | 2 | 1 | 1 | 5 |
| Total | 1 | 93 | 1 | 5 | 100 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →27 pathogenic / likely-pathogenic (of 31) ClinVar copy-number / structural variants overlap OPRM1 — these span large chromosomal regions, not the gene specifically, and are excluded from the counts above. Explore in CNV tools →
Protein Context — Lollipop Plot
OPRM1 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
Personalized Perioperative Analgesia Platform (PPAP) for Pediatric Spine Fusion Surgery (sIRB)
RECRUITINGHIIT vs MICT During Pregnancy and Health and Birth Outcomes in Mothers and Children
RECRUITINGElectroacupuncture Therapy in Reducing Chronic Pain in Patients After Breast Cancer Treatment
ACTIVE NOT RECRUITINGHome-based Transcranial Direct Current Stimulation (tDCS) Compared to Duloxetine: Non-inferiority Clinical Trial (FIBROSTIM)
RECRUITINGPrecision Analgesia for Cardiac Surgery
NOT YET RECRUITINGPredicting and Preventing Adverse Maternal and Child Outcomes of Opioid Use Disorder in Pregnancy
RECRUITINGParaphilic Disorders and Other Conditions With Risk for Sexual Violence: a Case-control Study
RECRUITINGEfficacy of a Prediction Model-based Algorithm to PREVENT Drug-induced Impulse Control Disorders in Parkinson's Disease
NOT YET RECRUITINGExternal Resources
Links to major genomics databases and tools