VDR rs11568828: What Your Genotype Means
The rs11568828 variant is a well-studied single nucleotide polymorphism located in the promoter region of the VDR gene. Commonly known as the Cdx-2 binding site polymorphism, it influences how effectively the caudal-type homeobox 2 transcription factor binds DNA to modulate vitamin D receptor expression. In population studies, this variant has been linked with subtle shifts in intestinal calcium absorption, bone mineral density, and colorectal cancer susceptibility.
What each genotype means
Enhanced VDR promoter activity
You carry two copies of the A allele in the VDR Cdx-2 promoter region, which has been shown in molecular studies to bind the CDX2 transcription factor with higher affinity and increase receptor transcription compared to the G allele. In epidemiological research, this genotype has been linked to slightly higher bone mineral density and altered colorectal cancer risk, although overall clinical evidence remains modest and conflicting across different populations. Because this variant confers a health predisposition rather than a direct diagnosis, lifestyle factors like dietary calcium and vitamin D status remain primary influences on your bone and bowel health.
Carried by approximately 55% to 70% of individuals of European ancestry, but less frequent in East Asian populations where it occurs in roughly 25% to 35% of individuals.
Intermediate VDR promoter activity
You carry one A allele and one G allele in the VDR Cdx-2 promoter region, resulting in intermediate transcriptional efficiency of the vitamin D receptor. Studies evaluating bone mineral density and colorectal cancer susceptibility show intermediate or mixed risk profiles for heterozygous carriers relative to homozygotes. Findings across various ancestral cohorts are variable and limited, meaning this genotype alone does not determine your clinical bone health or cancer risk.
Found in approximately 25% to 35% of individuals of European ancestry and roughly 45% to 50% of East Asian populations.
Reduced VDR promoter activity
You carry two copies of the G allele in the VDR Cdx-2 promoter region, which is associated with lower CDX2 binding affinity and approximately 70% reduced basal transcriptional activity in experimental assays compared to the A allele. In some observational cohorts, this genotype has been associated with lower bone mineral density and altered susceptibility to colorectal neoplasms, though epidemiological findings remain limited and contradictory across different ethnic groups. This genetic variation represents a subtle predisposition and does not establish a clinical condition.
Observed in roughly 2% to 5% of European populations, but much more prevalent in East Asian populations where it occurs in approximately 15% to 25% of individuals.
Genomic Location and Biological Mechanism
The single nucleotide polymorphism rs11568828 is located on chromosome 12 in the promoter region upstream of the VDR gene. It involves a single base substitution, typically described in genomic literature as a guanine (G) to adenine (A) sequence alteration within an intestine-specific regulatory sequence. This regulatory motif acts as the specific binding site for Cdx-2 (caudal-type homeobox 2), an essential transcription factor predominantly active in intestinal epithelial cells. Functional biochemical assays demonstrate that the A allele provides a stronger binding affinity for Cdx-2 compared to the G allele. As a result, the A allele generally facilitates higher transcriptional activity and increased receptor abundance in intestinal tissue. Conversely, the G allele is associated with lower binding efficiency and reduced promoter drive, which may attenuate localized vitamin D signaling pathways within the gut epithelium.
The Biological Role of the VDR Gene
The VDR gene encodes the vitamin D receptor, an intracellular nuclear hormone receptor that binds calcitriol, the active hormonal form of vitamin D. Once activated by calcitriol, the receptor heterodimerizes with the retinoid X receptor (RXR) and docks at specific vitamin D response elements across the genome. This interaction regulates dozens of downstream target genes responsible for calcium and phosphate balance, mucosal integrity, cellular differentiation, and immune modulation. In enterocytes lining the gut, robust VDR expression is critical for transcellular calcium transport, which ultimately dictates how much dietary calcium enters the bloodstream. Beyond mineral homeostasis, vitamin D signaling also exerts anti-proliferative and pro-differentiation effects in the gastrointestinal tract, acting as a homeostatic brake on cellular turnover.
Associated Health Predispositions and Evidence Strength
Because rs11568828 modulates transcription in intestinal tissue, epidemiological research has primarily evaluated its links to bone health and gastrointestinal malignancies. Carrying the G allele—and particularly the GG genotype—has been correlated in multiple cohorts with slightly reduced bone mineral density and an elevated risk for osteoporotic fractures, presumably due to suboptimal intestinal calcium uptake. In oncology cohorts, altered VDR activity has also been evaluated for its relationship to colorectal neoplasia and tumor development. However, the overall strength of scientific evidence remains classified as limited. Across global study populations, effect sizes are modest and findings are frequently mixed. Some cohorts report clear associations, whereas others show negligible risk differences once nutritional factors, lifestyle, and linkage disequilibrium with other VDR variants are controlled.
Ancestral Diversity and Allele Distribution
The frequency of rs11568828 varies considerably across geographic and ancestral populations. The G allele is present at an estimated frequency of 15% to 20% among individuals of European ancestry, meaning the A allele is the predominant sequence variant in European-derived cohorts. By contrast, the G allele occurs at a higher frequency in East Asian populations, where it approaches 45%, resulting in a significantly higher proportion of heterozygous and homozygous G carriers. In African populations, the A allele is observed at frequencies exceeding 70%. Because baseline allele distributions and background dietary calcium intake differ widely across global populations, the phenotypic impact of any individual genotype cannot be extrapolated reliably across ancestries without accounting for ethnic context.
Clinical Utility: What This Means for You
Genotype information for rs11568828 does not represent a clinical diagnosis of osteoporosis or colorectal cancer, nor does it guarantee that you will ever develop these conditions. Complex conditions like bone density loss and gastrointestinal diseases develop through intricate interactions among hundreds of common genetic variants, aging, diet, physical activity, and environmental factors. Possessing a genotype linked to lower transcriptional drive merely reflects a slight biological predisposition that can often be balanced through standard healthy habits. Individuals should not adjust dietary calcium supplements, start high-dose vitamin D, or initiate screening protocols based on direct-to-consumer genetic readouts alone. If you have personal or family concerns regarding bone health or colorectal screening, discuss appropriate clinical tests and vitamin D blood work with a qualified healthcare provider.
How common is this variant?
The G allele occurs at an estimated frequency of 15% to 20% in populations of European ancestry, while reaching approximately 45% in East Asian populations and under 30% in African populations.
Frequently asked questions
Does having the rs11568828 GG genotype mean I will get osteoporosis?
No. The GG genotype represents a modest statistical risk factor rather than a definitive cause of bone density loss. Bone strength is determined by many genetic markers, weight-bearing exercise, hormonal health, dietary calcium, and serum vitamin D levels.
Can taking extra vitamin D counteract the effects of this variant?
While adequate vitamin D and calcium intake support healthy bone turnover, you should not take high-dose supplements solely based on your genetic status. Nutritional needs should always be guided by laboratory blood tests (such as serum 25-hydroxyvitamin D) and advice from your doctor.
How does rs11568828 affect colorectal cancer risk?
The VDR gene helps regulate cell differentiation and cellular growth in the digestive tract. Some observational studies have reported altered colorectal cancer risk in individuals with lower VDR expression, but the evidence remains limited, modest, and inconsistent across different ancestral groups.
Is rs11568828 the same as the Fok1 or Bsm1 polymorphisms?
No. While Fok1, Bsm1, Taq1, and Cdx-2 (rs11568828) are all genetic markers within the VDR gene, they sit at different positions and operate via distinct mechanisms. Fok1 alters the protein's start site, whereas rs11568828 specifically changes a transcription factor binding site in the gene's promoter region.
Sources & further reading
Educational information only, last refreshed 9/11/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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