rs1799971
Opioid receptor variant A118G
What this position does
This changes the main receptor that opioid painkillers act on. It has been studied for morphine dose requirements after surgery and for response to naltrexone in treating alcohol dependence.
What each result means
| If you carry | What it means |
|---|---|
| No copies of the effect version AA | You have the common version of the receptor The common version on both copies. |
| One copy AG | One copy of the variant receptor Some studies find slightly higher opioid dose requirements after surgery. Findings are mixed. |
| Two copies GG | Two copies of the variant receptor Uncommon in Europe, common in East Asia. Associated in some studies with higher opioid dose requirements, though the evidence is not strong enough to change prescribing. |
Worth knowing. Not currently used to guide prescribing. Never adjust a painkiller dose on this.
How common each version is
| Ancestry group | G (the effect version) | |
|---|---|---|
| African | 0.9% | |
| American | 20.0% | |
| East Asian | 39.3% | |
| European | 16.2% | |
| South Asian | 41.8% |
1000 Genomes Project phase 3, via Ensembl, retrieved 2026-09-23. These groupings are coarse and flatten a great deal of internal diversity, particularly within Africa. A variant being common somewhere tells you where a piece of your ancestry probably comes from, and nothing else.
How many people carry each result
| Ancestry group | AA | AG | GG |
|---|---|---|---|
| African | 649 / 661 | 12 / 661 | 0 / 661 |
| European | 353 / 503 | 137 / 503 | 13 / 503 |
| East Asian | 185 / 504 | 242 / 504 | 77 / 504 |
| South Asian | 153 / 489 | 263 / 489 | 73 / 489 |
| American | 224 / 347 | 107 / 347 | 16 / 347 |
Counts of people, not modelled frequencies: every one of the 2,504 individuals sequenced by the 1000 Genomes Project phase 3, tallied by the genotype they carry. Deriving these from allele frequencies instead would assume random mating inside each group and undercount the homozygotes.
How to find out which you have
If you have taken a test with 23andMe, AncestryDNA, MyHeritage, Family Tree DNA, TellMeGen or Living DNA, this position is very likely already in the raw data file they gave you. You do not need another test.
One thing to watch if you look it up by hand: testing companies report some positions from one DNA strand and some from the other, and the file does not say which. Read the letters as they appear and you will get the opposite of the truth for some positions. Sequencings resolves that automatically.
Source
Coordinates and allele pair verified against Ensembl GRCh37. Direction of effect verified against VEP protein consequences or 1000 Genomes population frequency. Category: Trait.
Where this fits
Common questions
What is rs1799971?
rs1799971 is a position in the OPRM1 gene on chromosome 6. This changes the main receptor that opioid painkillers act on. It has been studied for morphine dose requirements after surgery and for response to naltrexone in treating alcohol dependence.
What does it mean if I have GG at rs1799971?
Two copies of the variant receptor. Uncommon in Europe, common in East Asia. Associated in some studies with higher opioid dose requirements, though the evidence is not strong enough to change prescribing.
What does it mean if I have AA at rs1799971?
You have the common version of the receptor. The common version on both copies.
How do I find out my rs1799971 genotype?
If you have taken a home DNA test, this position is very likely in the raw data file you were given. Sequencings reads that file in your browser without uploading it, and resolves which DNA strand each position was reported from, which is the step most manual lookups get wrong.
This is reference information, not medical advice, and not a diagnosis. See the medical disclaimer. Category: Trait.