Genetics of Vitamin D

Vitamin D is both a nutrient and a hormone with broad immune-regulatory functions. Genetic variants in vitamin D synthesis, transport, receptor, and metabolism genes influence vitamin D status and immune response capacity, relevant to COVID-19 and Long COVID.

This page is for educational and informational purposes only. Not a diagnostic tool. Always consult a qualified healthcare provider.

What is Vitamin D?

Vitamin D (calcitriol) regulates over 200 genes, including many immune function genes. Vitamin D deficiency is widespread globally and has been associated with increased susceptibility to respiratory infections, autoimmunity, and inflammatory conditions. Genetic variation in the vitamin D pathway — including CYP27B1 (activation), CYP24A1 (inactivation), GC (transport protein), and VDR (receptor) — significantly influences individual vitamin D status independent of sun exposure and dietary intake. VDR variants affect the downstream transcriptional responses to vitamin D across immune, bone, and metabolic tissues.

Biological pathways commonly discussed in relation to Vitamin D

Research into Vitamin D Metabolism and Immune Regulation has highlighted several biological pathways that may be relevant. Genetic variants within these pathways may influence individual susceptibility, symptom severity, or the trajectory of the condition.

Vitamin D Synthesis

CYP2R1 performs 25-hydroxylation of vitamin D3 in the liver, and CYP27B1 performs 1-alpha-hydroxylation (activation) in the kidney and immune cells. Variants affect the efficiency of these activation steps.

Vitamin D Transport

GC (vitamin D-binding protein) transports vitamin D metabolites in the bloodstream. GC variants significantly affect circulating 25-hydroxyvitamin D levels and bioavailability.

Vdr Signalling

The vitamin D receptor (VDR) mediates the genomic effects of calcitriol. VDR variants (BsmI, FokI, ApaI, TaqI) affect transcriptional activity and have been studied in relation to immune function and disease susceptibility.

Vitamin D Immune

Vitamin D regulates innate immunity (antimicrobial peptide induction), adaptive immunity (Treg promotion, Th1 suppression), and cytokine production. VDR is expressed on virtually all immune cells.

Key genes studied in relation to Vitamin D

The following genes have been studied in relation to Vitamin D Metabolism and Immune Regulation. These genes span the biological pathways most commonly discussed in this area of research.

VDR

VDR encodes the nuclear receptor for 1,25-dihydroxyvitamin D3, regulating immune function, calcium homeostasis, and gene expression.

CYP27B1

CYP27B1 encodes 1-alpha hydroxylase, the enzyme that converts 25-hydroxyvitamin D to the active form 1,25-dihydroxyvitamin D3.

GC encodes the vitamin D binding protein (VDBP), which transports vitamin D metabolites in the circulation.

CYP24A1

CYP24A1 encodes 24-hydroxylase, which inactivates active vitamin D to prevent toxicity and regulate vitamin D signaling.

RXRA

RXRA encodes RXR-alpha, a nuclear receptor that forms heterodimers with VDR and PPAR receptors, modulating gene expression.

CYP2R1

CYP2R1 is the primary hepatic enzyme that hydroxylates vitamin D3 to 25-hydroxyvitamin D, the main circulating form of vitamin D.

DHCR7

DHCR7 encodes the enzyme that converts 7-dehydrocholesterol (the vitamin D precursor) to cholesterol, competing with vitamin D synthesis from UV exposure.

CAMP

CAMP encodes cathelicidin (LL-37), a vitamin D-induced antimicrobial peptide with broad-spectrum activity against bacteria, viruses, and fungi.

9 genes total studied in relation to Vitamin D across the ChronicDNA dataset.

Genetic variants commonly discussed

The following genetic variants (SNPs) are found in genes that have been studied in relation to Vitamin D. Each variant represents a position in the genome where individuals may carry different alleles.

rs2228570VDR rs1544410VDR rs703842CYP27B1 rs4646536CYP27B1 rs731236VDR rs7975232VDR

22 variants total across genes studied in relation to Vitamin D.

How personal DNA data may provide educational insights

Consumer DNA files from 23andMe, AncestryDNA, and MyHeritage contain raw SNP data. When you upload your file to ChronicDNA, the analysis engine checks your genotype against a curated panel of 80+ genes selected for their relevance to Long COVID, ME/CFS, and connected biological pathways - some of which may relate to areas such as Vitamin D.

This is not a diagnostic service. Genetic variants do not determine whether you have Vitamin D, nor do they predict your clinical outcomes. The report is educational - it explains which variants you carry, what the research says about them, and how they fit into the biological pathways most relevant to chronic illness. All results should be discussed with a qualified healthcare provider.

Related conditions and pathways

Vitamin D shares biological pathways and genetic associations with the following related conditions and areas of research.

Immune Dysregulation Autoimmunity Long Covid Inflammation Immune Regulation

Frequently asked questions

How do vitamin D genetics relate to COVID-19 and Long COVID?

Vitamin D deficiency has been associated with increased COVID-19 severity in observational studies. Genetic variants reducing vitamin D activation (CYP27B1), transport (GC), or receptor responsiveness (VDR) may contribute to functional vitamin D insufficiency even at normal serum levels.

Which vitamin D genes are most studied?

Key genes include VDR, GC, CYP27B1, CYP2R1, CYP24A1, and RXRA. These cover the full pathway from synthesis activation to receptor signalling.

What do VDR variants mean?

VDR variants including BsmI (rs1544410), FokI (rs2228570), ApaI (rs7975232), and TaqI (rs731236) affect vitamin D receptor activity. They have been studied in relation to immune function, autoimmunity, bone density, and cancer risk. Their individual effects are modest.

Can genetics explain vitamin D deficiency?

Partially — GC and CYP2R1 variants are strong genetic determinants of circulating 25-hydroxyvitamin D levels. However, sun exposure, skin pigmentation, diet, and body composition are the primary determinants of vitamin D status in most individuals.

Explore DNA insights

If you already have DNA data from 23andMe, AncestryDNA, or MyHeritage, upload your raw file to ChronicDNA and receive a personalised educational report covering genes studied in relation to Vitamin D and connected biological pathways.

Get Your Personalised DNA Report

Informational and educational only · Not a diagnostic tool · GDPR compliant

9 genes · 22 variants analysed in relation to Vitamin D