The TCN2 776C>G polymorphism correlates with vitamin B12 cellular delivery in healthy adult populations

Rita Castro, Madalena Barroso, Mónica Rocha, Ruben Esse, Ruben Ramos, Paula Ravasco, Isabel Rivera, Isabel Tavares de Almeida

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Objectives: Vitamin B12, or B12, is an essential nutrient for humans, and its deficiency is a public health problem, especially in elderly population. Around 30% of circulating total B12 levels are attached to transcobalamin II (TCN2), being referred as holotranscobalamin (holo-TC), and representing the biologically active fraction. After cellular uptake, B12 participates in the homocysteine (Hcy) metabolism. The potential influence of the described TCN2 776C>G polymorphism upon B12 intracellular delivery is a current target of research and we aimed to investigate its biochemical significance upon a healthy adult population. Design and methods: The TCN2 776C>G polymorphism was screened by PCR-RFLP in 122 individuals. Concentrations of plasma total B12, holo-TC, total Hcy and folate, as well as red blood cell folate, were determined. Results and conclusions: The studied polymorphism is common in the Portuguese population and significantly affects holo-TC but neither total B12 nor total Hcy plasma concentrations, confirming that the TCN2 776C>G genotype exerts a significant influence upon B12 cellular delivery.

Original languageEnglish (US)
Pages (from-to)645-649
Number of pages5
JournalClinical Biochemistry
Issue number7-8
StatePublished - May 2010

All Science Journal Classification (ASJC) codes

  • Clinical Biochemistry


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