What you carry at this position in your DNA and what research says about it.
Obesity and BMI Risk: 10/10 evidence, 14 publications.
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Sample genotype (not yours): C/C
Typical Body Mass Index and Obesity Risk
Carrying two copies of the common C allele is associated with a typical body mass index and lower risk of obesity. It is also linked to slightly higher cognitive performance.
What this genotype means: Typical body mass index; Slightly higher cognitive scores.
Sample genotype (not yours): C/T
Slightly Increased Obesity and BMI Risk
Carrying one copy of the T allele is associated with a slight increase in average body mass index and obesity risk. Regular physical activity can help mitigate this genetic predisposition.
What this genotype means: Slightly higher average BMI; Increased susceptibility to weight gain.
Sample genotype (not yours): T/T
Increased Obesity and BMI Risk
Carrying two copies of the T allele is associated with a higher average body mass index and increased risk of obesity. Active lifestyles and dietary management are highly effective at counteracting this genetic tendency.
What this genotype means: Higher average body mass index; Elevated risk of obesity.
Gene function and biological role
Gene Function: MTCH2 encodes mitochondrial carrier 2, an outer mitochondrial membrane protein that plays a key role in mitochondrial biology and metabolism. It is highly active in adipose tissue and is involved in adipocyte differentiation and lipid accumulation, making it a critical player in energy balance [1]. Research has consistently linked MTCH2 expression and its genetic variants to body mass index and obesity risk across diverse populations [2]. It also participates in apoptosis and mitochondrial recruitment of specific proteins.
Variant Impact: Located within an intron of the MTCH2 gene, rs3817334 is one of the most robustly replicated genetic markers for body mass index and obesity. The single-nucleotide change influences the expression of MTCH2 and neighboring genes in metabolic tissues [1]. Large-scale genome-wide association studies have repeatedly identified this locus as a key determinant of adult and childhood body size [2]. The variant is also associated with other complex traits, including cognitive function and cellular measurements.
Key Insight: Physical activity has been shown to actively counteract the genetic weight-gain predisposition associated with this variant.
Location: MTCH2. Chromosome 11 · 11p11.2 · 47.6 Mb
Estimated prevalence by population
Global 40.9%; European 34.5%; African 54.7%; East Asian 47.7%; South Asian 46.5%; Americas 33.2%; Ashkenazi 40.8%; Finnish 37.3%; Middle Eastern 29.3%; Amish 11.5%.
Estimated CC genotype frequency.
Global 45.3%; European 48.5%; African 38.5%; East Asian 42.7%; South Asian 43.4%; Americas 48.8%; Ashkenazi 46.2%; Finnish 47.5%; Middle Eastern 49.7%; Amish 44.8%.
Estimated CT genotype frequency.
Global 13.8%; European 17.0%; African 6.8%; East Asian 9.6%; South Asian 10.1%; Americas 18.0%; Ashkenazi 13.1%; Finnish 15.1%; Middle Eastern 21.1%; Amish 43.8%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Cardiovascular & Metabolic
Obesity & Body Composition
Body Mass Index. Evidence: 10/10. Source: PMID 20935630. Typical BMI.
Blood Cell & Iron Traits
Platelet Count. Evidence: 8/10. Source: PMID 39024449. Slightly Higher.
Neurology & Mental Health
Cognitive Performance
Cognitive Function. Evidence: 6/10. Source: PMID 29844566. Slightly Higher.
Addiction & Reward
Smoking Behavior. Evidence: 6/10. Source: PMID 28443625. Typical.
Showing effects for C/T genotype
Body Mass Index. Evidence: 10/10. Source: PMID 20935630. Slightly Higher BMI.
Platelet Count. Evidence: 8/10. Source: PMID 39024449. Typical.
Cognitive Function. Evidence: 6/10. Source: PMID 29844566. Typical.
Smoking Behavior. Evidence: 6/10. Source: PMID 28443625. Slightly Higher Risk.
Showing effects for T/T genotype
Body Mass Index. Evidence: 10/10. Source: PMID 20935630. Higher BMI.
Smoking Behavior. Evidence: 6/10. Source: PMID 28443625. Higher Risk.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Two copies of the protective C allele are associated with a lower average body mass index compared to carrying the T allele [1]. This genetic profile is linked to typical metabolic rate and mitochondrial function in fat tissue. Large-scale studies have confirmed that this genotype helps maintain a healthier weight baseline across various ancestries. Additionally, the C allele is associated with slightly higher general cognitive function and intelligence scores [2]. Platelet counts may also be slightly higher, though this remains within the normal physiological range [3].
Typical body mass index; Slightly higher cognitive scores.
Sample genotype: CT (Heterozygous)
One copy of the T allele at this locus is associated with a modest increase in body mass index and a higher predisposition to weight gain [1]. This effect is driven by the variant's influence on MTCH2 expression, which alters mitochondrial energy balance in metabolic tissues. Research indicates that the genetic influence on BMI is particularly prominent during childhood and young adulthood [2]. Interestingly, the impact of this variant on body weight can be significantly modified by lifestyle factors, such as physical activity [3]. The T allele is also associated with a slightly higher tendency toward smoking behaviors [4].
Slightly higher average BMI; Increased susceptibility to weight gain.
Sample genotype: TT (Homozygous)
Two copies of the T allele are associated with the highest genetic risk for elevated body mass index and obesity at this locus [1]. The double dose of the T allele alters mitochondrial carrier 2 protein levels, shifting cellular energy regulation toward fat storage. This genetic association has been replicated across multiple global populations, including European, East Asian, and African ancestries [2]. Longitudinal studies show that this variant's effect on body weight often manifests early in life and persists into adulthood [3]. However, physical activity has been shown to successfully attenuate the weight-promoting effects of this genotype [4].
Higher average body mass index; Elevated risk of obesity.
Variants with shared genetic architecture
rs10838738 · MTCH2 Gene · Chr 11 · Obesity and BMI Risk
rs713586 · ADCY3 Gene · Chr 2 · Obesity and BMI Risk
rs7498665 · SH2B1 Gene · Chr 16 · Obesity and Weight Risk
Genetic studies of body mass index yield new insights for obesity biology.
Association analyses of 249,796 individuals reveal 18 new loci associated with body mass index.
Diversity and scale: Genetic architecture of 2068 traits in the VA Million Veteran Program.
The genetics of childhood obesity and interaction with dietary macronutrients.
Genome-wide physical activity interactions in adiposity - A meta-analysis of 200,452 adults.
Recapitulation of genome-wide association studies on body mass index in the Korean population.
Content updated August 2026.
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