Genetic variant

rs671 a variant in the ALDH2 gene

rs671 is a single-letter difference in the ALDH2 gene, on chromosome 12. ClinVar, the public archive of variant interpretations, lists it as drug response: linked to how the body handles certain medicines. It has been reported in connection with Alcohol sensitivity, acute and Alcohol dependence, among others. Carrying it does not, on its own, mean you have or will develop any condition.

ClinVar: Drug response
Drug Response
Chromosome 12

What is this?

Your DNA is a long sequence of four letters. At a few million positions, people commonly differ by a single letter; each of those positions is called a SNP (“snip”), and rs671 is the catalogue number of one of them, in the ALDH2 gene. Which letters you carry there — one copy from each parent — is your genotype.

ALDH2 (aldehyde dehydrogenase 2 family member): This protein belongs to the aldehyde dehydrogenase family of proteins. Aldehyde dehydrogenase is the second enzyme of the major oxidative pathway of alcohol metabolism. Two major liver isoforms of aldehyde dehydrogenase, cytosolic and mitochondrial, can be distinguished by their electrophoretic mobilities, kinetic properties, and subcellular localizations.
Gene description from NCBI Gene

rs671 is a classic SNP, well known in a sense through the phenomena known as the 'alcohol flush', al...
From SNPedia

Why might it matter?

ClinVar records this variant as drug response, meaning linked to how the body handles certain medicines. A classification describes the variant, not you: what it means for one person depends on their genotype, their family history and often on other genes and circumstances.

Conditions it has been reported with

Alcohol sensitivity, acute
Alcohol dependence
Susceptibility to hangover
Esophageal cancer
Alcohol-related
Susceptibility to
AMED syndrome, digenic
ethanol response - Toxicity
ALDH2-related disorder
Nitroglycerin
Poor response to

Listed in ClinVar submissions for this variant. Being listed is a report of an association, not a statement that the variant causes the condition in any given person.

Do I have this variant?

If you have taken a consumer DNA test (23andMe, AncestryDNA and similar), you can download its raw data file and check. Create a free account, upload the file, and this page will show the letters you carry at rs671, if your test read this position.

Connect this with your blood results

A gene is a fixed instruction; a blood test shows what your body is doing now. CheckMyBloods reads the two side by side, so a variant can be set against the markers it could plausibly affect.

Blood markers do not diagnose a genetic condition, and a variant does not explain a blood result on its own. Together, with symptoms and family history, they give a clinician context.

Upload blood results

What should I do next?

Find out whether you carry it. Reading about a variant says nothing about you until you know your genotype.
Put it in context. Add your blood results, so the variant can be read against what your body is doing.
Ask questions. Dr. Hemsworth, our AI assistant, can explain this variant and your results in plain English.
Take anything that worries you to a professional. A GP or genetic counsellor can order a confirmatory test and interpret it with your history.

This page is general information drawn from public research databases. It cannot diagnose anything, and it is not a substitute for advice from a doctor or genetic counsellor who knows your history.

Technical details

dbSNP ID: rs671
Gene: ALDH2
Position (GRCh38): chr12:111803961
Variant type: snv
Consequence: missense variant
ClinVar classification: drug response