What GC rs2282679 Means in Your 23andMe Raw Data

What does GC rs2282679 mean in my 23andMe raw data? In a 23andMe raw file, rs2282679 is a marker in the GC gene. It is associated with lower total 25-hydroxyvitamin D and may be linked to vitamin D binding protein (DBP) related differences. It is not a diagnosis, not a vitamin D level, and not a reason to ignore a low blood test.

Reading the raw data line

A 23andMe raw data line for rs2282679 may show the rsID, chromosome, position, and two letters. Those two letters are chip-, build-, and strand-dependent. Do not hand-map a fixed allele such as C or A. Instead, use a tool that reports whether you carry zero, one, or two copies of the allele associated with lower total 25-hydroxyvitamin D.

What the GC gene and rs2282679 mean

The GC gene provides instructions for vitamin D binding protein (DBP). DBP is a carrier protein. Almost all 25-hydroxyvitamin D in blood rides on DBP, and a smaller fraction is free or bioavailable. The marker rs2282679 is a single base pair in the GC gene. It is associated with a small average difference in total 25-hydroxyvitamin D and may be linked to DBP-related differences. This article describes the association, not a fixed production effect.

The figure shows an illustrative stepwise pattern, not exact ng/mL values. The bars are relative and illustrative. Zero, one, or two copies of the lower-total-associated allele are shown. The genotype does not report your current vitamin D level.

Why total 25-hydroxyvitamin D may be lower

Most routine lab tests measure total 25-hydroxyvitamin D: the DBP-bound plus the free fraction. rs2282679 is associated with lower total 25-hydroxyvitamin D and may be linked to DBP-related differences. A low total result may be interpreted alongside DBP and, when relevant, free or bioavailable testing. This is not something you can resolve from the genotype alone.

Practical next steps

Get a 25-hydroxyvitamin D blood test. If the result is low, discuss it with a clinician. Consider DBP or free/bioavailable testing only as follow-up when relevant. Do not ignore a low blood test because of this genotype. A low total 25-hydroxyvitamin D can still be a true deficiency.

Common mistakes

Treating rs2282679 as a vitamin D deficiency gene is the main mistake. It is not. It is a normal inherited marker associated with lower total 25-hydroxyvitamin D. It does not stop your skin making vitamin D from sunlight, and it does not stop your gut absorbing it from food. Another mistake is ignoring a low blood test because your genotype says you are supposed to be low.

Effect size and interpretation can vary by ancestry, skin pigmentation, sun exposure, diet, and study population. No single expected effect size applies to everyone.

See it in your own raw data

If you have already downloaded your 23andMe raw file, search for rs2282679 in a text editor with Ctrl+F or Command+F. The matching line shows your result. Because raw files can use different genome builds or strand orientations, rely on the rsID and a tool's interpretation rather than assuming a fixed allele label.

healthosx.com/dna

The download steps for 23andMe, on the page itself.

healthosx.com/dna

The short version: what is worth acting on, first.

The free DNA tool parses your file in the browser. The initial DNA story needs no payment, email, or account. The full free report opens after a one-time email code. The HealthOS report includes the GC vitamin D binding protein finding from your own data. You can use Ask your DNA to ask about your result.