rs9939609 FTO
FTO risk variant homozygous. Associated with increased BMI and obesity risk (1.67x odds).
What is rs9939609?
rs9939609 is a single-nucleotide polymorphism (SNP) in the FTO gene (Fat mass and obesity-associated (alpha-ketoglutarate-dependent dioxygenase)). Each person carries two copies, one from each parent, so a result is reported as a pair of letters such as AA. The table below describes what studies associate with each genotype; the association is statistical, across populations, and is not a diagnosis.
What does each rs9939609 genotype mean?
| Genotype | Association | What the evidence says | Confidence |
|---|---|---|---|
| AA | elevated | FTO risk variant homozygous. Associated with increased BMI and obesity risk (1.67x odds). | 88% |
| AT / TA | slightly elevated | One copy of FTO risk variant. Moderately increased obesity risk. | 85% |
| TT | typical / lower | Typical obesity risk at FTO locus. | 88% |
How common is the A allele of rs9939609?
Minor-allele frequency by population (gnomAD / 1000 Genomes):
| European | 42.0% |
|---|---|
| East Asian | 12.0% |
| African | 45.0% |
| South Asian | 30.0% |
| Admixed American | 35.0% |
| Global | 34.0% |
Which drugs have annotations for rs9939609?
PharmGKB clinical annotations (level 1A is the strongest evidence, 4 the weakest):
| Drug | Annotation type | Evidence level |
|---|---|---|
| interferon alfa-2a | Efficacy | 3 |
| recombinant | Efficacy | 3 |
| interferon alfa-2b | Efficacy | 3 |
| ribavirin | Efficacy | 3 |
| """interferon alfa-2a | Efficacy | 3 |
| recombinant"" | Efficacy | 3 |
| ""interferon alfa-2b | Efficacy | 3 |
| ""ribavirin""" | Efficacy | 3 |
Is rs9939609 on 23andMe and AncestryDNA chips?
Yes — it is genotyped directly on 23andMe V3, 23andMe V4, 23andMe V5, AncestryDNA V1, AncestryDNA V2. Orviva reads it from a raw-data export without imputation.
Sources
Upload your 23andMe, AncestryDNA or WeGene raw file → · Ask G2: “What is my genotype at rs9939609 and what does it mean for me?”
Genetic associations describe risk across populations, not a diagnosis for any one person. Most variants shift risk modestly and act alongside lifestyle, environment and other genes. Consumer DNA chips do not read every position and can be wrong at any single one. For general education only; talk to a clinician or genetic counsellor before acting on anything here, and never change a prescribed medicine without your prescriber.