{{Rsnum
|rsid=1799971
|Gene=OPRM1
|Chromosome=6
|position=154039662
|Orientation=plus
|GMAF=0.1901
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(A;A)
|geno2=(A;G)
|geno3=(G;G)
|Gene_s=OPRM1
}}{{ population diversity
| geno1=(A;A)
| geno2=(A;G)
| geno3=(G;G)
| CEU | 70.8 | 27.4 | 1.8
| HCB | 40.1 | 47.4 | 12.4
| JPT | 29.2 | 47.8 | 23.0
| YRI | 100.0 | 0.0 | 0.0
| ASW | 93.0 | 7.0 | 0.0
| CHB | 40.1 | 47.4 | 12.4
| CHD | 31.5 | 51.9 | 16.7
| GIH | 30.7 | 55.4 | 13.9
| LWK | 98.2 | 1.8 | 0.0
| MEX | 63.8 | 32.8 | 3.4
| MKK | 93.6 | 6.4 | 0.0
| TSI | 69.6 | 28.4 | 2.0
| HapMapRevision=28
}}The [[rs1799971]](G) allele in exon 1 of the mu opioid receptor [[OPRM1]] gene causes the normal amino acid at residue 40, asparagine (Asn), to be replaced by aspartic acid (Asp). In the literature this SNP is also known as A118G, N40D, or Asn40Asp.

Carriers of at least one [[rs1799971]](G) allele appear to have stronger cravings for alcohol than carriers of two [[rs1799971]](A) alleles, and are thus hypothesized to be more at higher risk for [[alcoholism]]. {{PMID|17207095}}

However, subsequent research results are mixed, and there are other studies both agreeing or disagreeing with this finding [PMID 15525999, PMID 9399694, PMID 12960749]

Among 200+ alcoholics treated with [[naltrexone]], [[rs1799971]](G) carriers receiving the drug (even without behavioral intervention) had an increased percentage of days abstinent (p = .07) and a decreased percentage of heavy drinking days (p = .04) if treated with naltrexone vs. placebo, whereas [[rs1799971]](A;A) homozygotes showed no medication differences. Upon treatment with [[naltrexone]], 87% of [[rs1799971]](G) carriers had a good clinical outcome, compared with only 55% of individuals with the (A;A) genotype (odds ratio, 5.75, CI: 1.88-17.54){{PMID|18250251|OA=1
}}

This SNP may also influence the response to opioids such as [[heroin]], [[codeine]] or [[morphine]]. 

A study of 200 Chinese heroin addicts found increased frequency for the [[rs1799971]](G) allele compared to non-addicts (40% vs 29%) {{PMID|11338173}}; but another study of Han Chinese addicts found no difference {{PMID|11933204}}.

[http://blog.23andme.com/2009/09/22/snpwatch-evidence-for-gene-environment-interaction-in-alcoholism/ 23andMe blog] Alcoholism related
*[[rs1799971]](A;A) severe alcoholism 2x 
*[[rs1799732]](I;I) severe alcoholism 1.85x

{{ neighbor
| rsid = 17181017
| distance = 1
}}

{{omim
|desc=OPIOID RECEPTOR, MU-1; OPRM1
|id=600018
|rsnum=1799971
}}
{{PMID Auto
|PMID=19860800
|Title=Initial Evidence of an Association Between OPRM1 and Adolescent Alcohol Misuse
|OA=1
}}

{{PharmGKB
|RSID=rs1799971
|Name_s=OPRM1: A118G
|Gene_s=OPRM1
|Feature=
|Evidence=PubMed ID:19605407
|Annotation=Risk or phenotype-associated allele(s): AG/GG. Phenotype: The G118 SNP (AG/GG) was associated with a 27% increase in plasma alfentanil concentration (P=0.034), a 54% increase in alfentanil dose (P=0.009). Despite the increased alfentanil self-administration, the G118 SNP was associated with a 52% increase in verbal analogue pain scores over the same period of time (P=0.047). Study size: 99. Study population/ethnicity: patients with acute pain.
|Drugs=alfentanil
|Drug Classes=
|Diseases=Pain
|Curation Level=Curated
|PharmGKB Accession ID=PA165110399
}}

{{PMID Auto
|PMID=20112002
|Title=A118G Polymorphism of OPRM1 Gene is Associated with Schizophrenia
}}

{{PharmGKB
|RSID=rs1799971
|Name_s=OPRM1: A118G
|Gene_s=OPRM1
|Feature=
|Evidence=PubMed ID:17156920
|Annotation=Based on a study at 207 patients treated with morphine, carriers of OPRM1 GG genotype required 93% higher morphine dose compared to carriers of AA genotypes (p = 0.012).
|Drugs=morphine
|Drug Classes=
|Diseases=Pain
|Curation Level=Curated
|PharmGKB Accession ID=PA161748324
}}

{{PharmGKB
|RSID=rs1799971
|Name_s=OPRM1: A118G; Asn40Asp
|Gene_s=OPRM1
|Feature=
|Evidence=PubMed ID:11751037; PubMed ID:12627468; PubMed ID:18004207
|Annotation=Several studies found an enhanced cortisol response to naloxone among subjects with the Asp40 variant. A study in healthy individuals who were of European Americans or Asian ancestry found that participants with one or two Asp40 alleles had a significantly greater cortisol response to naloxone than Asn40 homozygotes, but the effect was limited to European Americans.
|Drugs=naloxone
|Drug Classes=
|Diseases=
|Curation Level=Curated
|PharmGKB Accession ID=PA162191297
}}

{{PharmGKB
|RSID=rs1799971
|Name_s=OPRM1: A118G; Asn40Asp
|Gene_s=OPRM1
|Feature=
|Evidence=PubMed ID:15525999; PubMed ID:15608594; PubMed ID:17339526; PubMed ID:18250251; PubMed ID:8072460
|Annotation=This variant is associated with increased receptor affinity, alcohol-induced euphoria, and risk for alcohol use disorders. Alcoholic subjects with an Asp40 allele tend to have better clinical outcomes ( increased percentage of days abstinent and decreased percentage of heavy drinking days) when treated with naltrexone for alcoholism compared to those with the Asn40/Asn40 genotype.
|Drugs=ethanol; naltrexone
|Drug Classes=
|Diseases=Alcoholism
|Curation Level=Curated
|PharmGKB Accession ID=PA162360620
}}

{{PMID Auto
|PMID=21277709
|Title=No evidence of association between 118A&gt;G OPRM1 polymorphism and heroin dependence in a large Bulgarian case-control sample
|OA=1
}}

{{PMID Auto
|PMID=21160491
|Title=Haplotype block structure of the genomic region of the mu opioid receptor gene
|OA=1
}}

{{PMID Auto
|PMID=22046326
|Title='Smoking Genes': A Genetic Association Study
|OA=1
}}

{{PMID Auto
|PMID=22071118
|Title=Ethnic-specific meta-analyses of association between the OPRM1 A118G polymorphism and alcohol dependence among Asians and Caucasians
}}

{{PMID|16623937|OA=1
}} A clinical genetic method to identify mechanisms by which pain causes depression and anxiety.

{{PMID|16887046|OA=1
}} The mu-opioid receptor gene and smoking initiation and nicotine dependence.

{{PMID|18384978|OA=1
}} Association of candidate genes with antisocial drug dependence in adolescents.

{{PMID|18433502|OA=1
}} Association between single nucleotide polymorphisms in the mu opioid receptor gene (OPRM1) and self-reported responses to alcohol in American Indians.

{{PMID|18518884}} Association between mu-opioid receptor-1 102T>C polymorphism and intermediate type 2 diabetes phenotypes: results from the Quebec Family Study (QFS).

{{PMID|18518925|OA=1
}} Genetic susceptibility to heroin addiction: a candidate gene association study.

{{PMID|18690117|OA=1
}} Gene and gene by sex associations with initial sensitivity to nicotine in nonsmokers.

{{PMID|18698231|OA=1
}} Polymorphisms affecting gene transcription and mRNA processing in pharmacogenetic candidate genes: detection through allelic expression imbalance in human target tissues.

{{PMID|18725235|OA=1
}} Bidirectional translational research: Progress in understanding addictive diseases.

{{PMID|19008867}} OPRM1 gene is associated with BMI in Uyghur population.

{{PMID|19053977|OA=1
}} OPRM1 Asn40Asp predicts response to naltrexone treatment: a haplotype-based approach.

{{PMID|19103668|OA=1
}} Expansion of the human mu-opioid receptor gene architecture: novel functional variants.

{{PMID|19258022|OA=1
}} Now or Later? An fMRI study of the effects of endogenous opioid blockade on a decision-making network.

{{PMID|19335651|OA=1
}} Candidate genes for cannabis use disorders: findings, challenges and directions.

{{PMID|19775452|OA=1
}} Do genetic predictors of pain sensitivity associate with persistent widespread pain?

{{PMID|20100356|OA=1
}} PCA-based bootstrap confidence interval tests for gene-disease association involving multiple SNPs.

{{PMID|20194481|OA=1
}} Association of mu-opioid receptor variants and response to citalopram treatment in major depressive disorder.

{{PMID|21029375|OA=1
}} OPRM1 gene variants modulate amphetamine-induced euphoria in humans.

{{PMID|21423693|OA=1
}} Effect sizes in experimental pain produced by gender, genetic variants and sensitization procedures.

{{PMID|22211341|OA=1
}} Variation in OPRM1 and risk of suicidal behavior in drug-dependent individuals.

{{PMID|22309038}} Possible Association Between OPRM1 Genetic Variance at the 118 Locus and Alcohol Dependence in a Large Treatment Sample: Relationship to Alcohol Dependence Symptoms.

{{PMID|22457278|OA=1
}} Association of polymorphisms of the mu opioid receptor gene with the severity of HIV infection and response to HIV treatment.

{{PMID|22587755}} Pharmacogenetically driven treatments for alcoholism: are we there yet?

{{PMID Auto
|PMID=22978509
|Title=Convergence of Genome-Wide Association and Candidate Gene Studies for Alcoholism
|OA=1
}}

{{GET Evidence
|gene=OPRM1
|aa_change=Asn40Asp
|aa_change_short=N40D
|impact=pharmacogenetic
|qualified_impact=Insufficiently evaluated pharmacogenetic
|inheritance=unknown
|quality_scores=Array
|dbsnp_id=rs1799971
|overall_frequency_n=957
|overall_frequency_d=10018
|overall_frequency=0.0955281
|n_genomes=13
|n_genomes_annotated=0
|n_haplomes=15
|n_articles=0
|n_articles_annotated=0
|nblosum100=-1
|autoscore=0
|webscore=N
|summary_short=Better clinical outcome with ethanol and naltrexone.
}}

[[Naltrexone Treatment Response]]

{{PMID Auto
|PMID=23560613
|Title=Association study of OPRM1 polymorphisms with Schizophrenia in Han Chinese population
|OA=1
}}

{{PMID Auto
|PMID=23651028
|Title=OPRM1 rs1799971 polymorphism and opioid dependence: evidence from a meta-analysis
}}

{{PMID Auto
|PMID=23803057
|Title=Gene Polymorphisms of OPRM1 A118G and ABCB1 C3435T May Influence Opioid Requirements in Chinese Patients with Cancer Pain
}}

{{PMID Auto
|PMID=23454283
|Title=Low frequency genetic variants in the μ-opioid receptor (OPRM1) affect risk for addiction to heroin and cocaine
|OA=1
}}

{{ClinVar
|ALT=G
|CAF=0.8099; 0.1901
|CHROM=6
|CLNACC=RCV000010146.1
|CLNALLE=1
|CLNDBN=Reclassified - variant of unknown significance
|CLNHGVS=NC_000006.11:g.154360797A>G
|CLNSRC=OMIM Allelic Variant
|CLNSRCID=600018.0001
|COMMON=1
|Disease=Reclassified - variant of unknown significance
|FwdALT=G
|FwdREF=A
|GENEINFO=OPRM1:4988
|GENE_ID=4988
|GENE_NAME=OPRM1
|REF=A
|RSPOS=154360797
|Reversed=0
|SAO=0
|SSR=0
|Tags=PM;PMC;SLO;VLD;G5;HD;GNO;KGPhase1;KGPROD;OTHERKG;PH3;LSD;OM
|VC=SNV
|VP=0x050168000000150517110101
|WGT=0
|dbSNPBuildID=89
|rsid=1799971
}}

{{PMID Auto
|PMID=24407958
|Title=Risky alcohol consumption in young people is associated with the fatty acid amide hydrolase gene polymorphism C385A and affective rating of drug pictures
}}

{{PMID Auto
|PMID=22781865
|Title=Testing multiple levels of influence in the intergenerational transmission of alcohol disorders from a developmental perspective: the example of alcohol use promoting peers and mu-opioid receptor M1 variation.
|OA=1
}}

{{PMID Auto
|PMID=22841130
|Title=Shared and unique genetic contributions to attention deficit/hyperactivity disorder and substance use disorders: a pilot study of six candidate genes.
}}

{{PMID Auto
|PMID=22954510
|Title=Delta and kappa opioid receptor polymorphisms influence the effects of naltrexone on subjective responses to alcohol.
|OA=1
}}

{{PMID Auto
|PMID=23222260
|Title=Opioid receptors control viral replication in the airways.
}}

{{PMID Auto
|PMID=23302985
|Title=The effect of OPRM1 and COMT genotypes on the analgesic response to intravenous fentanyl labor analgesia.
}}

{{PMID Auto
|PMID=23318993
|Title=Opioid receptor polymorphism A118G associated with clinical severity in a drug overdose population.
}}

{{PMID Auto
|PMID=24951719
|Title=Genetic Variation of the Mu Opioid Receptor (OPRM1) and Dopamine D2 Receptor (DRD2) is Related to Smoking Differences in Patients with Schizophrenia but not Bipolar Disorder
}}

{{PMID Auto
|PMID=25086307
|Title=Endogenous opioid system influences depressive reactions to socially painful targeted rejection life events
}}
{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | FTDNA2}}
{{on chip | FTDNA}}
{{on chip | HumanOmni1Quad}}
{{on chip | Illumina Human 1M}}