GC rs2282679: Understanding Your Vitamin D Binding Protein Variant
The rs2282679 variant is a common genetic change located in the GC gene, which provides instructions for making the vitamin D-binding protein. Research indicates that this specific variant is a primary genomic predictor of circulating 25-hydroxyvitamin D levels in the blood.
What each genotype means
Typical 25-hydroxyvitamin D levels
You carry two copies of the major allele (often reported as T on the complementary strand in older literature). Research associates this genotype with typical baseline circulating 25-hydroxyvitamin D concentrations and a standard increase in blood levels following vitamin D supplementation. Because diet, sun exposure, and overall health strongly influence vitamin D status, carrying this genotype does not guarantee optimal levels.
Carried by approximately 50% to 55% of individuals of European ancestry, and common across many global populations.
Intermediate 25-hydroxyvitamin D levels
You carry one copy of the variant allele (often designated G on the complementary strand), which is statistically associated with slightly lower circulating 25-hydroxyvitamin D levels. Studies show this effect may be more noticeable during seasons or periods with limited sunlight exposure. Evidence is based on observational genome-wide association studies, and lifestyle factors like sun exposure and diet remain primary drivers of vitamin D status.
Carried by roughly 35% to 40% of people in European and Middle Eastern populations.
Lower 25-hydroxyvitamin D levels
You carry two copies of the minor allele, which has been linked in population studies to lower circulating total 25-hydroxyvitamin D concentrations and reduced circulating vitamin D-binding protein levels. Some intervention studies also report a modest reduction in the rate of 25-hydroxyvitamin D increase during supplementation compared to non-carriers. If you have concerns about your vitamin D levels or are considering supplementation, discuss checking your serum 25-hydroxyvitamin D levels with a healthcare provider.
Carried by approximately 6% to 10% of individuals of European ancestry, with similar low-to-moderate frequencies observed globally.
What is rs2282679?
The rs2282679 variant is a single nucleotide polymorphism (SNP) located within the GC gene on chromosome 4. Specifically, it is found in intron 12 of the gene. A SNP represents a variation at a single position in the DNA sequence among individuals. In the case of rs2282679, the variation involves the substitution of one nucleotide for another. Because this variant is located in a non-coding region of the gene, it does not change the amino acid sequence of the protein directly, but it is frequently studied because it serves as a reliable marker for how the body processes and transports vitamin D. Scientists use this SNP to better understand the genetic architecture that influences vitamin D status across different populations.
The Role of the GC Gene
The GC gene encodes the vitamin D-binding protein (VDBP). This protein is essential for human health because it acts as the primary transporter for vitamin D and its metabolites throughout the circulatory system. Once vitamin D is synthesized in the skin or ingested through diet, it must be transported to the liver and kidneys to be converted into its active form. The vitamin D-binding protein ensures that these molecules are carried safely through the bloodstream. Variations in the GC gene can influence the concentration or function of this protein, which in turn affects the total amount of 25-hydroxyvitamin D available in the blood. Understanding this gene is critical for researchers studying why some individuals maintain different levels of vitamin D despite similar environmental exposures.
Research and Associations
Large-scale genome-wide association studies (GWAS), such as the SUNLIGHT consortium, have identified a strong statistical link between rs2282679 and circulating 25-hydroxyvitamin D levels. The evidence for this association is robust, with some studies reporting highly significant p-values. While the variant is a strong predictor of vitamin D levels, it is important to note that vitamin D status is a complex trait influenced by many factors, including sunlight exposure, dietary intake, and supplement use. Some research suggests that the impact of the risk allele may be more pronounced in certain populations or during seasons with lower UV exposure. Because the evidence is based on statistical associations across large groups, it does not predict an individual's specific vitamin D level or health outcome with certainty.
What You Can Do With This Information
Genetic information regarding rs2282679 is primarily used for research purposes to understand the biological pathways of vitamin D. It is not a diagnostic tool for vitamin D deficiency. If you are concerned about your vitamin D levels, the most accurate approach is to consult with a healthcare provider who can order a standard blood test to measure your actual 25-hydroxyvitamin D concentration. Genetic variants do not replace clinical testing. If your doctor recommends vitamin D supplementation based on your blood work, follow their guidance regarding dosage and frequency. Never use genetic data to make independent medical decisions or to alter your intake of supplements or medications without professional medical advice.
How common is this variant?
The rs2282679 variant is common across diverse ancestral groups, including European, Middle Eastern, and African populations.
Frequently asked questions
Does having the CC genotype mean I am vitamin D deficient?
No, having a specific genotype does not mean you are deficient. Vitamin D levels are influenced by many factors, including diet, sun exposure, and lifestyle; a blood test is the only way to determine your actual status.
Should I take more vitamin D if I have the rs2282679 variant?
You should not change your supplement intake based on genetic results. Always discuss your vitamin D levels and any potential supplementation needs with your healthcare provider.
Is rs2282679 the only gene that affects vitamin D levels?
No, vitamin D levels are a complex trait influenced by multiple genes, including CYP2R1 and CYP24A1, as well as environmental factors. Genetic variants only account for a portion of the variation in vitamin D levels.
Where can I get my vitamin D levels tested?
You can request a 25-hydroxyvitamin D blood test from your primary care physician. This clinical test provides a direct measurement of your current vitamin D status.
Sources & further reading
Educational information only, last refreshed 10/16/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Common missense variant Thr436Lys in the vitamin D binding protein gene strongly associated with reduced circulating serum 25-hydroxyvitamin D concentrations.
A common regulatory variant in the GC gene (encoding Vitamin D Binding Protein) associated with circulating 25-hydroxyvitamin D levels.
This intronic variant in the vitamin D binding protein gene influences circulating 25-hydroxyvitamin D concentrations.
One of the two primary SNPs in the Vitamin D Binding Protein gene that determines a person's Vitamin D status and transport efficiency.