Vitamin E (CYP4F2, SCARB1)
CYP4F2 · SCARB1
Vitamin E (α-tocopherol) is transported in the blood partly within lipoproteins. Genetic studies have associated variants near CYP4F2, SCARB1 and the APOA cluster with measured levels. Rare disease-causing variants in TTPA can cause ataxia with vitamin E deficiency (AVED). Common variants do not determine an individual's vitamin E status.
Key points
- Three loci together explain about 1.7 percent of the variance in levels; CYP4F2 is the functional core.
- The slower CYP4F2 433M allele degrades less tocopherol, so carriers have higher levels.
- Because vitamin E travels in lipoproteins, the level partly follows lipid metabolism.
The markers
A genome-wide association study reported three loci for circulating α-tocopherol that together explained about 1.7 percent of variance in its study cohort (Major 2011). These include rs2108622 in CYP4F2, rs11057830 near SCARB1 and rs964184 in the APOA cluster. These are statistical associations, not a measurement of current vitamin E status. Rare loss-of-function variants in TTPA are a separate matter and can cause AVED.
What it means
The three common markers explain only a small share of the differences observed in the study. A genotype does not predict a current blood level or a need for supplements. CYP4F2 is also involved in response to warfarin; that relationship is discussed in the vitamin K and warfarin article.
Context
The loci are robustly replicated, but the explained share of variance is small. Genome shows the markers as technical evidence within the built-in panel 'Vitamins A-E'.
What Genome measures. The genotypes at rs2108622 (CYP4F2), rs11057830 (near SCARB1) and rs964184 (APOA cluster).
Related topics
Sources
- 1Major et al., 2011 Genome-wide association study identifies common variants associated with circulating vitamin E levels. Human Molecular Genetics 20:3876-3883. doi.org/10.1093/hmg/ddr296