Vitamin E (CYP4F2, SCARB1)

CYP4F2 · SCARB1

Vitamin E (α-tocopherol) travels in lipoproteins, so its blood level depends on both breakdown and lipid metabolism. The strongest common variants lie in CYP4F2 (breakdown), near SCARB1 (lipoprotein uptake) and in the APOA cluster (triglycerides). Rare loss-of-function in TTPA, by contrast, causes the hereditary disease AVED.

The markers

A genome-wide study found three loci for circulating α-tocopherol that together explain about 1.7 percent of the variance (Major 2011). rs2108622 (CYP4F2, V433M): CYP4F2 hydroxylates and disposes of tocopherols; the slower 433M allele degrades less, so carriers have higher levels. rs11057830 near SCARB1: SCARB1 is a lipoprotein receptor and influences uptake of fat-soluble vitamins. rs964184 in the APOA1/A5 cluster: here the vitamin E level follows triglyceride and lipoprotein metabolism, not a dedicated vitamin E gene. The α-tocopherol transfer protein TTPA is relevant not through common SNPs but through rare loss-of-function changes that cause ataxia with vitamin E deficiency (AVED).

What it means

The common variants shift the measured vitamin E level only moderately; diet and blood lipids weigh more. Because part of the genetics acts via lipid metabolism, a vitamin E value should always be read together with blood lipids. CYP4F2 is also pharmacogenetically important (see vitamin K).

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

Vitamin K (VKORC1)rsIDs, microarray and SNP lookupPharmacogenetics

Sources

  1. 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