MTNR1B rs10838738: What Your Genotype Means
The rs10838738 variant is a genetic marker located within the MTNR1B gene region. Research has associated this variant with variations in fasting blood glucose levels and an increased susceptibility to type 2 diabetes.
What each genotype means
Typical body mass index
This genotype is considered the baseline or reference state in many population studies regarding this variant. Research indicates that individuals with this genotype do not carry the specific genetic association linked to the slight increase in body mass index observed with the G allele. This result does not predict your personal health outcomes, as body weight is influenced by a complex interplay of genetics, lifestyle, and environment.
This is a common genotype found in a significant portion of the global population.
Slightly increased BMI association
Carrying one copy of the G allele has been associated in some genome-wide association studies with a modest increase in body mass index. This association is statistical in nature and reflects population-level trends rather than a direct cause of weight gain for any specific individual. Maintaining a balanced diet and regular physical activity remains the primary approach to managing body weight regardless of this genetic finding.
This heterozygous genotype is frequently observed across diverse ancestral populations.
Increased BMI association
Individuals with two copies of the G allele have been shown in research to have a statistically higher association with body mass index compared to those without the G allele. While this variant is linked to neuronal influences on body weight regulation, it is only one of many genetic and environmental factors that contribute to body composition. Please consult with a healthcare provider or registered dietitian if you have concerns about your weight or metabolic health.
This genotype is common, appearing in a substantial percentage of individuals across many global populations.
Understanding the Variant
The rs10838738 variant is a single nucleotide polymorphism (SNP), which is a common type of genetic variation where a single "letter" in the DNA sequence differs between individuals. This specific SNP is situated on chromosome 11. In the context of genetic research, SNPs like rs10838738 serve as signposts that help scientists identify regions of the genome that may influence specific biological traits or disease risks. While the variant itself is a small change in the genetic code, its location within or near the MTNR1B gene is significant because of the gene's role in metabolic processes. It is important to note that possessing a specific genotype for this SNP does not mean an individual will develop a condition; rather, it indicates a statistical association observed in large-scale population studies. These studies compare the frequency of genetic markers in groups of people with and without specific health traits to determine if a correlation exists.
The Role of the MTNR1B Gene
The MTNR1B gene provides instructions for making the melatonin receptor 1B, a protein that responds to the hormone melatonin. Melatonin is well-known for its role in regulating sleep-wake cycles, but the MTNR1B receptor is also expressed in pancreatic beta cells, which are responsible for producing insulin. Insulin is the hormone that helps control blood sugar levels. Research suggests that the signaling pathway involving this receptor may influence how the pancreas secretes insulin in response to glucose. When the function of this receptor is altered, it may affect the body's ability to maintain stable blood sugar levels. Because of this biological connection, scientists have focused on variants in this gene to understand how they might contribute to metabolic health, particularly regarding fasting glucose levels and the body's glucose regulation mechanisms.
Research and Evidence
The association between MTNR1B variants and glucose metabolism has been a subject of extensive study in the field of genomics. Large-scale genome-wide association studies (GWAS) have consistently identified variants in this gene region as being linked to higher fasting plasma glucose levels and an increased risk of type 2 diabetes. The evidence for these associations is considered moderate to strong in many populations of European descent. However, the strength and presence of these associations can vary significantly across different ancestral groups. Some studies have noted that while certain MTNR1B variants are strong predictors in one population, the same associations may not be replicated in others, such as East Asian or South Asian cohorts. This highlights the complexity of genetic risk, where the impact of a single variant is often influenced by the broader genetic background and environmental factors.
Population Frequency
The rs10838738 variant is considered common across most global populations. Because it is a common variant, a significant portion of the general population carries at least one copy of the risk-associated allele. The specific frequency of the alleles can fluctuate depending on the ancestral background of the group being studied, which is a standard observation in human genetics. These variations in frequency are part of the natural genetic diversity found in humans worldwide. Understanding these frequencies is essential for researchers when they conduct studies to ensure that findings are representative and to account for the differences in genetic architecture between diverse populations.
Interpreting Your Genetic Information
If you have access to your genetic data regarding the rs10838738 variant, it is important to view this information in the correct context. Genetic associations are statistical probabilities, not medical diagnoses. Having a genotype associated with higher fasting glucose does not guarantee that you will develop diabetes, nor does having a 'neutral' genotype guarantee that you will not. Many factors, including diet, physical activity, age, and overall family history, play a much larger role in determining your metabolic health than any single SNP. You cannot use this information to diagnose yourself or to make changes to prescribed medications. If you are concerned about your blood glucose levels or your risk for diabetes, the most effective step is to consult with a healthcare professional. They can provide personalized screenings and guidance based on your clinical history and current health status.
How common is this variant?
The rs10838738 variant is common in most populations, with allele frequencies varying by ancestry.
Frequently asked questions
Does this variant mean I have diabetes?
No. This variant is a genetic marker associated with a statistical increase in risk, not a diagnostic test for diabetes. Many people with this variant do not develop diabetes, and many people without it do.
Can I use this to change my diet?
Genetic information should not be used to make medical or dietary changes without consulting a doctor. A balanced diet and regular exercise are generally recommended for metabolic health regardless of your genotype.
Is this the only gene that affects blood sugar?
No. Blood sugar regulation is a complex process influenced by hundreds of different genes, as well as environmental and lifestyle factors. This variant is only one small piece of a much larger puzzle.
Should I get tested for this?
Clinical testing for this specific SNP is not standard practice for diabetes diagnosis. If you are concerned about your blood sugar, standard clinical tests like an A1C or fasting glucose test are the appropriate tools to use.
Sources & further reading
Educational information only, last refreshed 10/5/2026. Not medical advice — these associations describe population statistics, not individual predictions.
Curious what your genotype is for rs10838738?
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 — $29Related variants in MTNR1B
Common upstream variant of the melatonin receptor type 1B affecting circadian melatonin signaling and sleep-glycemia coupling.
This variant in the melatonin receptor 1B gene is significantly associated with REM sleep latency and the duration of melatonin secretion.
Links melatonin signaling to higher fasting blood glucose levels.