Markers / Condition
Which genes affect your vitamin D level?
Vitamin D is really a hormone, and getting it involves four separate steps: making the precursor, converting it in skin under ultraviolet light, activating it in the liver, and carrying it around in blood. There is a common variant at nearly every step, which is why measured vitamin D varies so much between people given the same sunlight.
The markers
| Marker | Gene | What it does | Evidence |
|---|---|---|---|
| rs2282679 | GC | Vitamin D binding protein | established |
| rs7041 | GC | The vitamin D carrier protein, second marker | established |
| rs12785878 | DHCR7 | How much vitamin D your skin can make | established |
| rs10741657 | CYP2R1 | Turning vitamin D into the usable form | established |
| rs2228570 | VDR | The vitamin D receptor, FokI | moderate |
Vitamin D binding protein
rs2282679 · GC
GC makes the protein that carries vitamin D around the body. This is the strongest common genetic influence on measured vitamin D levels, and it works by changing how much circulating vitamin D is bound.
Two copies: Two copies, so the lowest average vitamin D on a blood test
The vitamin D carrier protein, second marker
rs7041 · GC
A second position in the gene for the protein that transports vitamin D in blood. The two common forms bind it with different strength, which changes both your measured total and how much is actually free to use.
Two copies: You have the looser-binding version on both copies
How much vitamin D your skin can make
rs12785878 · DHCR7
DHCR7 controls the supply of the precursor your skin turns into vitamin D under ultraviolet light. Variants here rose in frequency in northern populations, which is what you would expect where sunlight is scarce for half the year.
Two copies: You carry two higher-vitamin-D copies
Turning vitamin D into the usable form
rs10741657 · CYP2R1
CYP2R1 is the liver enzyme that activates vitamin D after your skin makes it. It is the second of the two strongest common influences on your measured level.
Two copies: You carry two lower-level copies
The vitamin D receptor, FokI
rs2228570 · VDR
Having vitamin D and responding to it are different things. This change alters where the receptor protein starts, producing a slightly longer or shorter version, and the shorter one is somewhat more active.
Two copies: You have the longer receptor on both copies
Which versions do you carry?
All of these are readable from an ordinary home DNA test file, in your browser, without uploading it anywhere.
Read my fileCommon questions
Which genes affect your vitamin D level?
Vitamin D is really a hormone, and getting it involves four separate steps: making the precursor, converting it in skin under ultraviolet light, activating it in the liver, and carrying it around in blood. There is a common variant at nearly every step, which is why measured vitamin D varies so much between people given the same sunlight. The markers most often cited are rs2282679 in GC, rs7041 in GC, rs12785878 in DHCR7, rs10741657 in CYP2R1, rs2228570 in VDR.
What does rs2282679 do?
GC makes the protein that carries vitamin D around the body. This is the strongest common genetic influence on measured vitamin D levels, and it works by changing how much circulating vitamin D is bound. Carrying two copies: two copies, so the lowest average vitamin d on a blood test.
What does rs7041 do?
A second position in the gene for the protein that transports vitamin D in blood. The two common forms bind it with different strength, which changes both your measured total and how much is actually free to use. Carrying two copies: you have the looser-binding version on both copies.
What does rs12785878 do?
DHCR7 controls the supply of the precursor your skin turns into vitamin D under ultraviolet light. Variants here rose in frequency in northern populations, which is what you would expect where sunlight is scarce for half the year. Carrying two copies: you carry two higher-vitamin-d copies.
What does rs10741657 do?
CYP2R1 is the liver enzyme that activates vitamin D after your skin makes it. It is the second of the two strongest common influences on your measured level. Carrying two copies: you carry two lower-level copies.
Reference information, not medical advice and not a diagnosis. See the medical disclaimer.