What is rs526934 (TCN1) nd Why Does the Nutrient Zoomer Test for It?

Vitamin B12 binding protein

rs526934 is a genetic variant in the TCN1 gene, which encodes the B12‑binding protein haptocorrin. Variants at this site are linked to differences in how vitamin B12 is bound and carried in the bloodstream, so testing it can clarify inherited influences on B12 transport and circulating measures.

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rs526934 (TCN1)

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About rs526934 (TCN1)

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About rs526934 (TCN1)

Overview and History

rs526934 is a single nucleotide polymorphism (SNP) located in or near the TCN1 gene. TCN1 encodes transcobalamin I, commonly called haptocorrin, a glycoprotein that binds cobalamin (vitamin B12) in saliva and plasma and contributes to the pool of circulating, bound B12. Population genetics and genome-wide association studies have identified TCN1 variants as contributors to variation in total serum B12 levels. Biologically, haptocorrin helps protect dietary B12 in the gut and influences the distribution of B12 among carrier proteins, distinct from transcobalamin II which delivers B12 to cells.

Interpreting Highs and Lows

For a genetic marker like rs526934, “elevated” or “low” refers to alleles or genotypes associated with higher or lower TCN1 expression or haptocorrin levels in population studies. Alleles linked to higher haptocorrin may be associated with increased total serum B12 but do not necessarily reflect greater cellular availability. Alleles associated with lower haptocorrin can correlate with lower measured total B12 or altered proportions of B12 bound to carrier proteins. Interpretation requires the full Nutrient Zoomer context—direct B12 measures, functional markers (e.g., methylation or metabolic markers), and other genetic variants affecting B12 handling.

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Including rs526934 in the Nutrient Zoomer helps explain inherited variation in B12 binding and circulating measurements. It adds genetic context for discrepancies between total serum B12 and functional indicators, supporting a more precise view of B12 transport and individualized nutrient assessment.

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rs526934 (TCN1) FAQs

What is rs526934 (TCN1) and why is it important?

rs526934 is a genetic site in the TCN1 gene, which relates to the B12‑binding protein haptocorrin. Differences at this site are associated with how much B12 is bound in the blood and how B12 is distributed among carrier proteins. Knowing this can help explain why people with similar diets or labs may show different B12 measures.

What does it mean if my rs526934 (TCN1) levels are low?

For a genetic marker, “low” usually means carrying an allele linked to lower TCN1 expression or lower haptocorrin levels in studies. That pattern has been associated with lower total circulating B12 or shifts in the balance of B12 carrier proteins. Clinical meaning depends on the rest of the panel, including direct B12 measurements and functional markers.

What does it mean if my rs526934 (TCN1) levels are high?

A genotype associated with higher TCN1 or haptocorrin may correlate with higher total serum B12 in population data, even when cellular B12 delivery is unchanged. Elevated binding protein levels can influence lab results, so interpretation should consider other Nutrient Zoomer findings and functional indicators.

Why is this biomarker included in the Nutrient Zoomer?

rs526934 is included to provide genetic context for B12 transport and circulating measures. It helps clinicians separate effects of carrier-protein variation from true functional B12 patterns, improving the precision of nutrient assessment and personalized care planning.

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