What you carry at this position in your DNA and what research says about it.
Weight and Obesity Risk: 9/10 evidence, 37 publications.
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Sample genotype (not yours): T/T
Typical Weight and Lower Diabetes Risk
This genotype is associated with a lower genetic predisposition to obesity and type 2 diabetes.
What this genotype means: Lower genetic risk of obesity; Lower risk of type 2 diabetes; Slightly higher systolic blood pressure.
Sample genotype (not yours): C/C
Higher Risk of Obesity and Diabetes
Carrying two copies of the C allele is associated with the highest genetic predisposition to weight gain, obesity, and type 2 diabetes.
What this genotype means: Increased genetic risk of obesity; Higher risk of type 2 diabetes; Elevated risk of heart failure.
Sample genotype (not yours): T/C
Slightly Increased Risk of Weight Gain
Carrying one copy of the C allele is linked to a slightly higher body mass index and a modest increase in metabolic risks.
What this genotype means: Slightly higher body mass index; Modestly increased risk of type 2 diabetes; Slightly lower systolic blood pressure.
Gene function and biological role
Gene Function: The MC4R gene encodes the melanocortin-4 receptor, a crucial protein expressed in the brain's hypothalamus. This receptor plays a central role in energy homeostasis, appetite regulation, and weight control. It integrates signals from hormones like leptin to promote satiety and increase energy expenditure. Genetic variations that impair MC4R function are the most common cause of monogenic, early-onset obesity. Beyond weight, MC4R signaling is also involved in glucose metabolism and cardiovascular function.
Variant Impact: The rs6567160 variant is an intergenic genetic marker located near the MC4R gene. Although it does not change the amino acid sequence of the receptor itself, it is thought to influence how the gene is expressed or regulated. The C allele of this variant is strongly associated with higher body mass index and increased body fat. Conversely, the T allele is linked to slightly lower body weight but a minor increase in systolic blood pressure. This variant serves as a key marker for genetic predisposition to obesity and related metabolic conditions.
Key Insight: This genetic variant acts as a metabolic volume dial near the MC4R gene, where the C allele nudges the body toward storing more fat while the T allele slightly increases blood pressure.
Location: MC4R. Chromosome 18 · 18q21.32 · 60.2 Mb
Estimated prevalence by population
Global 62.4%; European 58.6%; African 65.8%; East Asian 67.0%; South Asian 42.3%; Americas 72.2%; Ashkenazi 63.3%; Finnish 68.7%; Middle Eastern 50.5%; Amish 47.6%.
Estimated TT genotype frequency.
Global 33.0%; European 35.9%; African 30.7%; East Asian 29.7%; South Asian 45.5%; Americas 25.6%; Ashkenazi 32.5%; Finnish 28.3%; Middle Eastern 41.1%; Amish 42.8%.
Estimated TC genotype frequency.
Global 4.6%; European 5.5%; African 3.6%; East Asian 3.3%; South Asian 12.2%; Americas 2.3%; Ashkenazi 4.2%; Finnish 2.9%; Middle Eastern 8.4%; Amish 9.6%.
Estimated CC genotype frequency.
Showing effects for T/T genotype
Cardiovascular & Metabolic
Obesity & Body Composition
Obesity. Evidence: 9/10. Source: PMID 25673413. Lower Risk.
Diabetes & Glycemic Traits
Type 2 Diabetes. Evidence: 10/10. Source: PMID 32541925. Lower Risk.
Heart Disease
Heart Failure. Evidence: 7/10. Source: PMID 40195560. Lower Risk.
Hypertension
Systolic Blood Pressure. Evidence: 8/10. Source: PMID 30224653. ~0.4 mmHg Higher.
Showing effects for C/C genotype
Obesity. Evidence: 9/10. Source: PMID 25673413. Increased Risk.
Type 2 Diabetes. Evidence: 10/10. Source: PMID 32541925. Increased Risk.
Heart Failure. Evidence: 7/10. Source: PMID 40195560. Increased Risk.
Systolic Blood Pressure. Evidence: 8/10. Source: PMID 30224653. Typical.
Showing effects for T/C genotype
Obesity. Evidence: 9/10. Source: PMID 25673413. Slightly Increased.
Type 2 Diabetes. Evidence: 10/10. Source: PMID 32541925. Slightly Increased.
Heart Failure. Evidence: 7/10. Source: PMID 40195560. Slightly Increased.
Systolic Blood Pressure. Evidence: 8/10. Source: PMID 30224653. ~0.2 mmHg Higher.
What this genotype means for the people who carry it
Sample genotype: TT (Homozygous)
Carrying two copies of the T allele is the most common genetic profile globally. Studies show that individuals with this genotype tend to have a lower body mass index and a reduced risk of developing obesity compared to those carrying the C allele. This protective effect extends to metabolic health, showing a lower risk of type 2 diabetes and heart failure. However, large-scale blood pressure studies have noted a very small increase in systolic blood pressure associated with the T allele. This minor cardiovascular trade-off is typically outweighed by the significant metabolic benefits of maintaining a healthier body weight. Active lifestyle habits continue to support this favorable baseline.
Lower genetic risk of obesity; Lower risk of type 2 diabetes; Slightly higher systolic blood pressure.
Sample genotype: CC (Homozygous)
Individuals with the C/C genotype carry two copies of the risk allele, which is strongly linked to higher body weight and adiposity. This genetic profile is associated with an increased body fat percentage, larger waist circumference, and a higher likelihood of obesity. The metabolic impact of this genotype also includes a significantly higher risk of developing type 2 diabetes. Furthermore, the increased strain of carrying excess weight is associated with an elevated risk of heart failure. Interestingly, this genotype is linked to a slightly lower systolic blood pressure, though this does not offset the overall metabolic risks. Proactive lifestyle strategies, including regular exercise and dietary management, are highly beneficial for managing these genetic tendencies.
Increased genetic risk of obesity; Higher risk of type 2 diabetes; Elevated risk of heart failure.
Sample genotype: TC (Heterozygous)
Having the T/C genotype means carrying one copy of the obesity-associated C allele near the MC4R gene. Research indicates that this single copy is associated with a moderate increase in body mass index, body fat percentage, and waist circumference. This genetic predisposition can make weight management slightly more challenging. Additionally, carriers face a slightly elevated risk of developing type 2 diabetes and heart failure. On the other hand, the presence of one T allele is associated with a slightly lower baseline systolic blood pressure compared to the T/T genotype. Focus on a balanced diet and regular physical activity can help mitigate these modest genetic risks.
Slightly higher body mass index; Modestly increased risk of type 2 diabetes; Slightly lower systolic blood pressure.
Variants with shared genetic architecture
rs2229616 · MC4R Gene · Chr 18 · Obesity and Weight Control
rs571312 · MC4R Gene · Chr 18 · Obesity and Weight Risk
rs17782313 · MC4R Gene · Chr 18 · Appetite and Weight Gain
Content updated August 2026.
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