CYP2R1 rs13361160: Vitamin D Metabolism and Your Genetics
The rs13361160 variant is a single nucleotide polymorphism located within the CYP2R1 gene, which plays a critical role in how the body processes vitamin D. Research indicates that this variant is associated with variations in circulating levels of 25-hydroxyvitamin D, the primary form of vitamin D measured in the blood.
What each genotype means
Typical vitamin D metabolism
This genotype represents the common version of the CYP2R1 gene associated with standard 25-hydroxylase enzyme activity. Research indicates that individuals with this genotype typically maintain baseline levels of circulating 25(OH)D, though overall vitamin D status remains influenced by environmental factors like sunlight exposure and dietary intake.
This is the most common genotype observed across most global populations.
Potential for altered vitamin D
Carrying one copy of the variant allele may be associated with subtle differences in how your body converts vitamin D into its active storage form, 25(OH)D. Studies suggest that genetic variation in CYP2R1 can influence circulating vitamin D levels, so you should discuss your vitamin D status and any supplementation needs with your healthcare provider.
The frequency of this heterozygous genotype varies significantly by ancestry, occurring more frequently in some populations than others.
Increased monitoring recommended
This genotype is associated with a higher likelihood of lower circulating 25(OH)D levels compared to the common genotype. Because CYP2R1 is a primary enzyme for vitamin D activation, you may want to consult with a clinician to monitor your vitamin D levels and determine if specific dietary or lifestyle adjustments are appropriate for you.
This homozygous genotype is less common and its prevalence varies widely depending on your ancestral background.
Understanding the SNP and Its Location
The rs13361160 variant is a specific genetic marker located within the CYP2R1 gene. In genomics, a single nucleotide polymorphism (SNP) represents a variation at a single position in the DNA sequence among individuals. The CYP2R1 gene itself is situated on chromosome 11p15.2 and consists of five exons. This gene is responsible for providing the instructions to create the CYP2R1 enzyme, which is a member of the cytochrome P450 family. These enzymes are essential for the metabolism of various substances, including hormones and vitamins. By studying SNPs like rs13361160, researchers aim to understand how subtle differences in our genetic code can influence biological processes, such as the efficiency with which our bodies convert vitamin D into its active, usable forms.
The Role of the CYP2R1 Gene
The CYP2R1 gene encodes the principal vitamin D 25-hydroxylase enzyme in humans. This enzyme is responsible for the first step in activating vitamin D, converting it into 25-hydroxyvitamin D, or 25(OH)D. This conversion is a vital process because 25(OH)D is the major circulating form of vitamin D in the bloodstream and is the standard marker used by clinicians to assess a person's vitamin D status. Once produced, this form of vitamin D helps the body maintain a proper balance of calcium and phosphate, which are necessary for bone health and dental development. Because CYP2R1 is the primary enzyme performing this conversion, any genetic variation that alters its expression or function can potentially impact the total amount of vitamin D available to the body, regardless of dietary intake or sun exposure.
Research Associations and Evidence Strength
The association between CYP2R1 variants and vitamin D levels is supported by moderate evidence from the GWAS Catalog and various peer-reviewed studies. Large-scale genome-wide association studies have repeatedly identified the CYP2R1 region as a major genetic determinant of vitamin D status. While some variants in this gene have been linked to significant changes in circulating 25(OH)D levels, the effect sizes can vary substantially across different populations and studies. It is important to note that while genetic factors are influential, they are only one piece of the puzzle. Environmental factors, such as latitude, skin pigmentation, diet, and lifestyle, also play major roles in determining vitamin D levels. Consequently, while rs13361160 is a recognized marker in nutrigenomics, it does not act in isolation, and its clinical impact is considered a subject of ongoing scientific investigation.
Population Frequency and Variability
The frequency of the rs13361160 variant is known to be variable across different ancestral populations. Genetic studies often observe that the prevalence of specific alleles can differ significantly between groups of European, African, Asian, and Middle Eastern descent. Because of this variability, a genotype that is common in one population may be rare in another. Researchers emphasize that these differences in allele frequency are a normal part of human genetic diversity. When interpreting data regarding this SNP, it is essential to consider the specific population context, as the association between a genotype and a physiological trait may not be uniform across all ethnic groups. Current research continues to map these frequencies to better understand the global landscape of vitamin D metabolism and how genetic predispositions might contribute to regional differences in vitamin D deficiency.
Interpreting Your Genetic Information
Information regarding the rs13361160 variant is intended for educational purposes and should not be used for medical diagnosis or to guide personal health decisions. While this SNP is associated with variations in vitamin D metabolism, it is not a diagnostic test for vitamin D deficiency or any related health condition. If you are concerned about your vitamin D levels, the most reliable approach is to consult with a healthcare professional or a registered dietitian. They can order appropriate blood tests to measure your actual 25(OH)D levels and provide personalized guidance on supplementation or lifestyle changes based on your clinical needs. Never make changes to your health regimen or supplement intake based solely on genetic reports without first discussing the implications with a qualified clinician or pharmacist who can interpret these results in the context of your overall health.
How common is this variant?
The frequency of the rs13361160 alleles is highly variable across different global populations, with specific distributions differing significantly between ancestral groups.
Frequently asked questions
Does having a specific CYP2R1 genotype mean I am vitamin D deficient?
No. A genetic variant is not a diagnosis. Vitamin D levels are influenced by many factors, including diet, sun exposure, and overall health, and a blood test is the only way to determine your current status.
Can I use this genetic information to decide how much vitamin D to take?
You should not use genetic information to determine supplement dosages. Always consult with your doctor or pharmacist to discuss appropriate vitamin D intake based on your blood test results and medical history.
Why do different studies show different results for CYP2R1?
Genetic associations can vary due to differences in study populations, environmental factors, and the complex nature of vitamin D metabolism. Science is an evolving field, and results often depend on the specific context of the research.
Is CYP2R1 the only gene that affects vitamin D levels?
No. Vitamin D metabolism is a complex process involving multiple genes, including those for the vitamin D receptor (VDR) and vitamin D-binding protein (GC). Many genetic and environmental factors work together to influence your levels.
Sources & further reading
Educational information only, last refreshed 10/26/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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This variant in the CYP2R1 gene, which encodes a key vitamin D 25-hydroxylase, is associated with altered serum 25-hydroxyvitamin D concentrations.
Associated with altered hepatic 25-hydroxylase enzyme levels and baseline circulating serum 25-hydroxyvitamin D concentrations.
Influences hepatic 25-hydroxylation efficiency and circulating 25-hydroxyvitamin D concentrations.
This variant in the CYP2R1 gene is associated with circulating 25-hydroxyvitamin D levels and, in rare cases, pathogenic variants in this gene can cause vitamin D-dependent rickets type 1B.
Affects the body's ability to convert sunlight into active Vitamin D.