UCP2 rs660339: What Your Genotype Means
The rs660339 variant is a common genetic change in the UCP2 gene that alters a single amino acid in the resulting protein. Research has associated this variant with differences in metabolic traits, such as body mass index, weight loss response, and markers of oxidative stress.
What each genotype means
Standard metabolic profile
This genotype is often referred to as the Ala/Ala variant. Research has observed that individuals with this genotype may have different physical fitness and metabolic responses compared to T-allele carriers, though findings are inconsistent across different populations and health conditions.
This is a common genotype found in many global populations, though its frequency varies significantly by ancestry.
Heterozygous metabolic variant
This genotype is known as the Ala/Val variant. Some studies suggest that carriers of the T allele may exhibit different physiological responses to exercise or metabolic stress compared to those with the CC genotype, but these associations are limited and not definitive.
This is a common genotype observed frequently in both European and Asian populations.
Valine homozygous variant
This genotype is known as the Val/Val variant. While some research has explored its potential link to lipid profiles or physical performance, the evidence remains limited and inconsistent, with some studies finding it to be quite rare in certain ethnic groups.
This genotype is generally less common than the CC and CT genotypes, with frequencies that vary widely by ancestry, being notably higher in some African populations and very low in others.
What is rs660339?
The rs660339 variant is a single nucleotide polymorphism (SNP) located within the UCP2 gene on chromosome 11. Specifically, it is a missense variant, meaning the change in the DNA sequence results in a different amino acid being incorporated into the UCP2 protein. In scientific literature, this is often referred to as the Ala55Val polymorphism, indicating that the protein may contain either an alanine or a valine at position 55. Because this change occurs in the coding region of the gene, it has the potential to influence the structure or function of the protein, which is why researchers have investigated its role in human metabolism and energy regulation.
The Role of the UCP2 Gene
The UCP2 gene encodes Uncoupling Protein 2, a protein found in the inner mitochondrial membrane of cells. Mitochondria are the powerhouses of the cell, responsible for generating energy in the form of ATP. UCP2 acts as a proton transporter that 'uncouples' the process of respiration from ATP production. By allowing protons to leak back into the mitochondrial matrix, UCP2 reduces the efficiency of energy production and helps regulate the production of reactive oxygen species (ROS). Because of this function, UCP2 is considered a key player in managing oxidative stress and cellular energy balance. Variations in this gene are hypothesized to influence how efficiently an individual's body burns energy and responds to metabolic stressors.
Research and Evidence
Evidence linking rs660339 to health outcomes is considered limited and often inconsistent across different populations. Some studies have observed associations between the C allele and increased risk of type 2 diabetes in specific groups, while others have linked the T allele to variations in body mass index or weight loss outcomes following bariatric surgery. Additionally, some research has explored connections between this variant and markers of cellular aging, such as telomere length, though results remain mixed. It is important to note that many of these findings are specific to certain ethnic groups or environmental contexts, and the effect sizes are generally small. Because of these conflicting results, the variant is not considered a definitive predictor of any specific health condition.
What You Can and Cannot Do
Information about your rs660339 genotype should be viewed as a point of scientific interest rather than a medical diagnostic tool. You cannot use this information to diagnose metabolic disorders, predict your exact fitness potential, or determine your risk for obesity. Genetic variants like rs660339 interact with a complex web of environmental factors, diet, and lifestyle choices, which often have a much larger impact on your health than a single SNP. If you are concerned about your metabolic health, weight management, or diabetes risk, it is essential to consult with a healthcare professional or a registered dietitian. They can provide personalized guidance based on your clinical history and blood work, which are far more reliable indicators of your current health status than genetic testing alone.
How common is this variant?
The rs660339 variant is common globally, with the C and T alleles appearing at significant frequencies across diverse ancestral populations.
Frequently asked questions
Is rs660339 a predictor of obesity?
While some studies have found associations between this variant and body mass index or fat distribution, it is not a reliable predictor of obesity. Obesity is a complex condition influenced by many genes and lifestyle factors.
Does my genotype mean I will develop diabetes?
No. Having a specific genotype for rs660339 does not mean you will develop diabetes. Genetic associations are statistical observations in large groups and do not determine individual health outcomes.
Can I change my UCP2 expression?
UCP2 expression is regulated by many factors, including diet and physical activity. While you cannot change your DNA sequence, healthy lifestyle choices are the primary way to support metabolic health.
Should I get tested for this variant?
There is no clinical recommendation to test for this variant. It does not provide actionable medical information that would change standard clinical care or treatment plans.
Sources & further reading
Educational information only, last refreshed 10/30/2026. Not medical advice — these associations describe population statistics, not individual predictions.
Curious what your genotype is for rs660339?
Upload a raw DNA file from 23andMe, AncestryDNA, MyHeritage, or FamilyTreeDNA and see this variant — plus thousands more — interpreted in your full report.
Get my report — $29