rs12785878 DHCR7
Reduced vitamin D synthesis from sunlight. DHCR7 variant affects cholesterol-to-vitamin D conversion.
What is rs12785878?
rs12785878 is a single-nucleotide polymorphism (SNP) in the DHCR7 gene (7-dehydrocholesterol reductase). Each person carries two copies, one from each parent, so a result is reported as a pair of letters such as TT. The table below describes what studies associate with each genotype; the association is statistical, across populations, and is not a diagnosis.
What does each rs12785878 genotype mean?
| Genotype | Association | What the evidence says | Confidence |
|---|---|---|---|
| TT | increased | Reduced vitamin D synthesis from sunlight. DHCR7 variant affects cholesterol-to-vitamin D conversion. | 85% |
| GT / TG | increased | Moderately reduced vitamin D synthesis. | 82% |
| GG | typical | Normal vitamin D synthesis from sunlight. | 85% |
How common is the T allele of rs12785878?
Minor-allele frequency by population (gnomAD / 1000 Genomes):
| European | 25.0% |
|---|---|
| East Asian | 5.0% |
| African | 8.0% |
| South Asian | 15.0% |
| Admixed American | 18.0% |
| Global | 15.0% |
Is rs12785878 on 23andMe and AncestryDNA chips?
Yes — it is genotyped directly on 23andMe V3, 23andMe V4, 23andMe V5, AncestryDNA V1, AncestryDNA V2. Orviva reads it from a raw-data export without imputation.
Sources
Upload your 23andMe, AncestryDNA or WeGene raw file → · Ask G2: “What is my genotype at rs12785878 and what does it mean for me?”
Genetic associations describe risk across populations, not a diagnosis for any one person. Most variants shift risk modestly and act alongside lifestyle, environment and other genes. Consumer DNA chips do not read every position and can be wrong at any single one. For general education only; talk to a clinician or genetic counsellor before acting on anything here, and never change a prescribed medicine without your prescriber.