rs1057868
A SNP in the POR gene on chromosome 7. Its most notable genotype is T;T: 1.6x higher overall CYP3A activity
- Gene
- POR
- Location
- Chr 775,985,688 (GRCh38)
- Highest magnitude
- 1.6Minor
- Tested on
- 23andMe, AncestryDNA
- Minor allele frequency
- 29%
Genotypes
As shown in 23andMe and AncestryDNA files.
On SNPedia: (C;C), (C;T), (T;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Related
Conditions, medicines and genes
Notes
From SNPedia
Show notes, about 140 words
rs1057868, also known as A503V, is a relatively common variant defining the POR*28 allele of the P450 (cytochrome) oxidoreductase POR gene. The POR gene encodes a protein involved in electron transport of cytochrome p450 enzymes such as CYP3A4, CYP3A5 and CYP3A7. A study of 251 individuals from two independent studies (182 patients treated with methadone and 69 patients with clozapine) for CYP3A activity found that CYP3A SNPs themselves did not predict particularly well inter-individual variability in overall CYP3A activity. However, rs1057868(T;T) individuals had a 1.6x increased CYP3A activity compared to rs1057868(C) carriers (n=182, p=0.004), and the finding was replicated in a second independent dataset. The authors conclude that this POR gene SNP is a better predictor of overall CYP3A activity than CYP3A SNPs.
Source and license
Adapted from rs1057868 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.
SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.