Does my DNA file show the alcohol flush gene?
Yes, if your file includes rs671 in the ALDH2 gene. An A at this position (the ALDH2*2 variant) slows the clearance of acetaldehyde, the compound behind facial flushing after alcohol, and it is common mainly in people of East Asian ancestry.
What to look for in your file
Search your raw data for rs671 (chromosome 12). Files report it as G and A; A is the ALDH2*2 variant.
| Your letters | Associated with |
|---|---|
| G G | Typical ALDH2 activity; acetaldehyde is cleared efficiently. |
| A G | One ALDH2*2 copy: reduced clearance. Facial flushing, nausea and a fast heartbeat after alcohol are typical. |
| A A | Two copies: very low enzyme activity and strong reactions to small amounts of alcohol. |
Brooks and colleagues (NIH/NIAAA) review the evidence that the flushing response is predominantly due to ALDH2 deficiency, and that people who flush have a much higher risk of esophageal cancer from alcohol consumption (PMID 19320537).
How common is it?
| Population group | A letter |
|---|---|
| African | 0.2% |
| Admixed American | 0.3% |
| East Asian | 17.4% |
| European | 0% |
| South Asian | 0% |
From those frequencies, about 29% of East Asian participants would be expected to carry one A and about 3% two. Elsewhere the A is rare.
Allele frequencies: 1000 Genomes phase 3 via Ensembl, read 2026-10-23. Genotype shares are Hardy–Weinberg estimates.
Limits
- Flushing can have other causes, and other genes take part in alcohol metabolism. G G does not rule those out.
- One marker is not your whole response to alcohol.
- This is educational information, not a diagnosis. Consumer raw data is not clinically validated for every marker.
What to do with it
- If you have an A, flushing is a signal of acetaldehyde build-up, not something to push through. Drinking less, or not at all, is the main lever.
- Choose drinks you enjoy without alcohol for social settings: sparkling water with citrus, alcohol-free beer, tea.
References
- Brooks PJ, Enoch MA, Goldman D, Li TK, Yokoyama A. The alcohol flushing response: an unrecognized risk factor for esophageal cancer from alcohol consumption. PLoS Med 2009;6:e50. PMID 19320537
- 1000 Genomes Project phase 3 allele frequencies for rs671, via Ensembl.
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