rs9939609
A SNP in the FTO gene on chromosome 16. Its most notable genotype is A;A: obesity risk and 1.6x risk for T2D
- Gene
- FTO
- Location
- Chr 1653,786,615 (GRCh38)
- Highest magnitude
- 3.0Important
- Tested on
- 23andMe, AncestryDNA
- Minor allele frequency
- 36%
Genotypes
As shown in 23andMe and AncestryDNA files.
- A;AMost notableBadobesity risk and 1.6x risk for T2D
- A;TBad1.3x risk for T2D; obesity risk
- T;TGoodlower risk of obesity and Type-2 diabetes
On SNPedia: (A;A), (A;T), (T;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Frequency
Share of each genotype in 11 HapMap populations.
- AverageA;A 15% A;T 42% T;T 43%
- European ancestry (Utah)A;A 18% A;T 57% T;T 26%
- Han Chinese (Beijing)A;A 2% A;T 26% T;T 72%
- Japanese (Tokyo)A;A 3% A;T 33% T;T 65%
- Yoruba (Nigeria)A;A 23% A;T 52% T;T 24%
- African ancestry (Southwest US)A;A 25% A;T 51% T;T 25%
- Chinese (Denver)A;A 3% A;T 27% T;T 71%
- Gujarati IndianA;A 8% A;T 36% T;T 56%
- Luhya (Kenya)A;A 35% A;T 47% T;T 18%
- Mexican ancestry (Los Angeles)A;A 5% A;T 35% T;T 60%
- Maasai (Kenya)A;A 26% A;T 53% T;T 21%
- TuscanA;A 24% A;T 44% T;T 32%
Related
Conditions, medicines and genes
Other FTO SNPs
- rs1421085C;C~1.7x increased obesity riskImportant
- rs1121980A;AModerate increase (2.76x) in risk for obesityImportant
- rs121918214A;GCarrier of a GDFD mutation (see text)Important
- rs16953002A;A1.32x increased risk of melanoma in those with low BMIMinor
- rs8050136A;A1.4x increased risk for T2D in some populationsMinor
- rs1558902A;AHigher BMI than normalTypical
- rs3751812G;GnormalTypical
- rs7195539A;Acommon genotypeTypical
Notes
From SNPedia
Show notes, about 620 words
rs9939609 is a SNP in the fat mass and obesity associated FTO gene, aka the "Fat Gene" dailytimes.com.pk. The original paper describing it is here . 2015 research suggests rs1421085 may be the causal snp. alzforum.org The researchers identified 10 different FTO SNPs in the first intron of the gene that associated with both BMI and type-2 diabetes. Because they all correlated with each other, they chose to examine one of the SNPs (rs9939609) in detail. rs9939609 has also been reported in a large study to be associated with type-2 diabetes. The risk allele (oriented to the dbSNP entry) is (A); the odds ratio associated with heterozygotes is 1.34 (CI 1.17-1.52), and for homozygotes, 1.55 (CI 1.3-1.84). In a different study, this SNP was found in a linkage block in the FTO gene with rs1121980; see rs1121980 for the association of this block with early onset obesity since it showed the strongest association. The increases in body mass index associated with rs9939609(A) carriers appears to begin at a young age and are maintained throughout adulthood, according to a study of 5,600+ Utah families. This SNP did not show any association with obesity, type-2 diabetes or any other related traits in a study of 3,210 Chinese subjects. Furthermore, the minor allele frequency was much lower in Chinese populations compared to populations of European descent. * Note: The three FTO SNPs, rs1421085, rs17817449, and rs9939609, are in strong linkage disequilibrium (pairwise r 2 >0.97), and there are two primary haplotypes, C-G-A (42.0 %) and T-T-T (55.5 %). 1,638 type 2 diabetes patients and 1,858 controls *rs9939609 in FTO (OR 1.14, 95% CI: 1.04-1.25, p = 0.006) A study of 3,000+ UK children indicated that (A;A) genotypes were less satieted (i.e. had greater appetite) than other genotypes, indicating this risk allele for obesity is likely to influence appetite. This SNP is also associated with (severe) obesity in a study of 927 Japanese patients. This SNP may contribute to variation in plasma C-reactive protein (CRP) levels independently of obesity; average CRP levels may be 12-14% higher per rs9939609(A) allele. This SNP is also associated with adult obesity in Mexicans. A longitudinal study of Finnish children concluded that the effect of rs9939609 on BMI only becomes evident after age 7, and that the FTO gene is not directly associated with energy intake or physical activity. Independent of fatness, the A-allele of the FTO SNP appears to increase mortality of a magnitude similar to smoking, but without a particular underlying disease pattern barring an increase in the risk of diseases of the nervous system. Each copy of the risk-allele A at rs9939609 was significantly associated with 0.45 kg/m(2) increase in BMI (95% confidence interval (CI): 0.16-0.74; P = 0.004) and 0.97 cm increase in waist circumference (95% CI: 0.21-0.65; P = 0.0002). Similar results were observed for rs8050136. may confer a modest susceptibility to obesity in an ethnicity-specific manner, but may be unlikely to contribute to a clinically significant diabetes risk. A small study (less than 700 women, divided into 4+ groups) concluded that over 3 & 6 months women in a weight-loss program who were informed they carried at least one rs9939609 risk allele lost slightly more weight than non-carriers.
A;A
This genotype produces higher levels of the appetite-stimulating hormone ghrelin, increasing your risk of obesity and type-2 diabetes by roughly 60%.
A;T
one copy of the genotype which increases production of the appetite stimulating hormone ghrelin. This increases your risk for obesity and Type-2 diabetes by approximately 20%.
Source and license
Adapted from rs9939609 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.
SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.