rs1229984
How fast alcohol becomes acetaldehyde
What this position does
This is the other half of the alcohol story. ALDH2 decides how fast acetaldehyde is cleared; ADH1B decides how fast it is made. The fast version produces acetaldehyde quickly, which makes drinking less pleasant and is strongly protective against alcohol dependence.
What each result means
| If you carry | What it means |
|---|---|
| No copies of the effect version CC | Standard version The common European genotype. Alcohol is converted at the usual rate. |
| One copy CT | One fast copy Alcohol is converted to acetaldehyde faster than usual, which is consistently associated with drinking less and with a lower risk of alcohol dependence. |
| Two copies TT | Two fast copies Very rapid conversion. Strongly associated with lower alcohol consumption. Common in East Asia, uncommon in Europe. |
How common each version is
| Ancestry group | T (the effect version) | |
|---|---|---|
| African | 0.2% | |
| American | 5.8% | |
| East Asian | 69.7% | |
| European | 2.9% | |
| South Asian | 2.0% |
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 | CC | CT | TT |
|---|---|---|---|
| African | 659 / 661 | 2 / 661 | 0 / 661 |
| European | 475 / 503 | 27 / 503 | 1 / 503 |
| East Asian | 45 / 504 | 215 / 504 | 244 / 504 |
| South Asian | 470 / 489 | 18 / 489 | 1 / 489 |
| American | 310 / 347 | 34 / 347 | 3 / 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 rs1229984?
rs1229984 is a position in the ADH1B gene on chromosome 4. This is the other half of the alcohol story. ALDH2 decides how fast acetaldehyde is cleared; ADH1B decides how fast it is made. The fast version produces acetaldehyde quickly, which makes drinking less pleasant and is strongly protective against alcohol dependence.
What does it mean if I have TT at rs1229984?
Two fast copies. Very rapid conversion. Strongly associated with lower alcohol consumption. Common in East Asia, uncommon in Europe.
What does it mean if I have CC at rs1229984?
Standard version. The common European genotype. Alcohol is converted at the usual rate.
How do I find out my rs1229984 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.