What you carry at this position in your DNA and what research says about it.
Bone Health and Density: 5/10 evidence, 19 publications.
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Sample genotype (not yours): C/C
Lower Bone Density and Higher Osteoporosis Risk
This genotype is associated with lower vitamin D receptor expression, which can reduce calcium absorption and bone strength. It may also carry a slightly lower rate of upper respiratory infections, on limited evidence.
What this genotype means: Lower bone mineral density; Increased risk of osteoporosis; Possibly fewer upper respiratory infections (limited evidence).
Sample genotype (not yours): C/T
Higher Bone Density and Protective Bone Health
Carrying one copy of the T allele enhances vitamin D receptor expression, supporting efficient calcium absorption and bone strength. It provides a protective effect against bone density loss.
What this genotype means: Higher bone mineral density; Reduced risk of osteoporosis; Faster metabolism of midazolam.
Sample genotype (not yours): T/T
Higher Bone Density
Two copies of the T allele maximize vitamin D receptor expression, promoting excellent bone mineralization. It is also linked to faster clearance of certain medications.
What this genotype means: Optimal bone mineral density; Strong protection against osteoporosis; Possibly more frequent upper respiratory infections (limited evidence).
Gene function and biological role
Gene Function: The VDR gene encodes the vitamin D receptor, a nuclear hormone receptor that binds to the active form of vitamin D [1]. This receptor acts as a transcription factor, regulating the expression of numerous genes involved in calcium absorption, bone mineralization, and immune system regulation [2]. Genetic variations in VDR can alter receptor abundance or function, directly impacting how the body utilizes vitamin D [3]. Consequently, these variations are widely studied for their influence on bone density, susceptibility to infections, and overall metabolic health [4].
Variant Impact: The rs11568820 variant, also known as the Cdx2 polymorphism, is located in the promoter region of the VDR gene [1]. This genetic change alters the binding site for the CDX2 transcription factor, which regulates VDR gene expression [3]. The T allele binds CDX2 with significantly higher affinity, leading to increased VDR receptor production [4]. Conversely, the C allele reduces promoter activity, resulting in lower receptor levels [5].
Key Insight: This variant acts like a volume dial for your vitamin D receptors, with the T allele turning up receptor production by enhancing transcription factor binding.
Location: VDR. Chromosome 12 · 12q13.11 · 47.9 Mb
Estimated prevalence by population
Global 45.7%; European 64.1%; African 4.0%; East Asian 33.5%; South Asian 45.9%; Americas 58.8%; Ashkenazi 56.7%; Finnish 71.5%; Middle Eastern 52.5%; Amish 68.5%.
Estimated CC genotype frequency.
Global 33.0%; European 31.9%; African 31.9%; East Asian 48.8%; South Asian 43.7%; Americas 35.7%; Ashkenazi 37.2%; Finnish 26.2%; Middle Eastern 39.9%; Amish 28.5%.
Estimated CT genotype frequency.
Global 21.3%; European 4.0%; African 64.1%; East Asian 17.8%; South Asian 10.4%; Americas 5.4%; Ashkenazi 6.1%; Finnish 2.4%; Middle Eastern 7.6%; Amish 3.0%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Organ Systems
Bone, Joint & Connective Tissue Health
Bone Mineral Density. Evidence: 4/10. Source: PMID 32236287. Lower Bone Density.
Immunity & Inflammation
Infection Susceptibility & Resistance
Respiratory Infection. Evidence: 3/10. Source: PMID 30132432. Lower Risk.
Pharmacogenomics
Anesthesia Response
Midazolam Metabolism. Evidence: 5/10. Source: PMID 22484315. Typical Metabolism.
Antimicrobial & Antiviral Response
Daclatasvir Metabolism. Evidence: 5/10. Source: PMID 29790402. Typical Metabolism.
Showing effects for C/T genotype
Bone Mineral Density. Evidence: 4/10. Source: PMID 32236287. Higher Bone Density.
Respiratory Infection. Evidence: 3/10. Source: PMID 30132432. Typical Risk.
Midazolam Metabolism. Evidence: 5/10. Source: PMID 22484315. Faster Metabolism.
Showing effects for T/T genotype
Respiratory Infection. Evidence: 3/10. Source: PMID 30132432. Higher Risk.
Daclatasvir Metabolism. Evidence: 5/10. Source: PMID 29790402. Faster Metabolism.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Having two copies of the C allele leads to lower transcriptional activity of the vitamin D receptor gene [1]. This reduction in receptor abundance can impair the body's ability to efficiently utilize vitamin D, which is essential for calcium absorption and bone mineralization [2]. Studies in postmenopausal women have linked this genotype to lower bone mineral density and an increased risk of developing osteoporosis [3]. On infection, the evidence runs the other way than the receptor biology suggests: one study of UK adults found fewer upper-respiratory infections with each copy of the C allele, though that finding was not confirmed in a separate cohort of children [4]. Individuals with this genotype may require higher dietary calcium and vitamin D intake to maintain optimal bone health [2].
Lower bone mineral density; Increased risk of osteoporosis; Possibly fewer upper respiratory infections (limited evidence).
Sample genotype: CT (Heterozygous)
Carrying one copy of the T allele increases the binding affinity of the CDX2 transcription factor to the VDR promoter [1]. This molecular change boosts the expression of vitamin D receptors, enhancing the body's sensitivity to circulating vitamin D [2]. Clinical studies have shown that individuals with this genotype tend to have higher bone mineral density, particularly in the spine and hip [3]. This protective effect helps lower the long-term risk of developing osteoporosis and bone fractures [1]. Its rate of upper respiratory infections is intermediate [4]. Furthermore, this genotype is associated with faster metabolism of certain medications, such as the sedative midazolam [5].
Higher bone mineral density; Reduced risk of osteoporosis; Faster metabolism of midazolam.
Sample genotype: TT (Homozygous)
Having two copies of the T allele maximizes the transcriptional activity of the VDR gene promoter [1]. This high-affinity genotype allows for robust binding of the CDX2 transcription factor, resulting in the highest levels of vitamin D receptor expression [2]. Consequently, individuals with this genotype exhibit superior bone mineral density and are highly protected against osteoporosis [3]. Upper respiratory infections are the one trait here that runs against the receptor biology: one study in UK adults reported a higher rate with each copy of this allele, although the finding was not confirmed in a separate cohort of children [4]. On the pharmacogenomic front, this genotype is associated with faster metabolism of medications like midazolam and the antiviral drug daclatasvir [5] [6].
Optimal bone mineral density; Strong protection against osteoporosis; Possibly more frequent upper respiratory infections (limited evidence); Faster metabolism of midazolam and daclatasvir.
Variants with shared genetic architecture
rs739837 · VDR Gene · Chr 12 · Skin Cancer Risk
rs1544410 · VDR Gene · Chr 12 · Osteoporosis Risk
rs731236 · VDR Gene · Chr 12 · Breast Cancer Prognosis
Association of Vitamin D Receptor Gene Polymorphisms with Metabolic Syndrome in Chinese Children.
Association of Vitamin D Gene Polymorphisms and Bone Mineral Density in Healthy young Saudi Females.
Vitamin D receptor genotype influences risk of upper respiratory infection.
Content updated August 2026.
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