The TCN2 776CNG polymorphism correlates with vitamin B(12) cellular delivery in healthy adult populations.
OBJECTIVE
Vitamin B(12), or B(12), is an essential nutrient for humans, and its deficiency is a public health problem, especially in elderly population. Around 30% of circulating total B(12) levels are attached to transcobalamin II (TCN2), being referred as holotranscobalamin (holo-TC), and representing the biologically active fraction. After cellular uptake, B(12) participates in the homocysteine (Hcy) metabolism. The potential influence of the described TCN2 776CNG polymorphism upon B(12) intracellular delivery is a current target of research and we aimed to investigate its biochemical significance upon a healthy adult population.


METHODS
The TCN2 776CNG polymorphism was screened by PCR-RFLP in 122 individuals. Concentrations of plasma total B(12), holo-TC, total Hcy and folate, as well as red blood cell folate, were determined.


CONCLUSIONS
The studied polymorphism is common in the Portuguese population and significantly affects holo-TC but neither total B(12) nor total Hcy plasma concentrations, confirming that the TCN2 776CNG genotype exerts a significant influence upon B(12) cellular delivery.
Research Institute for Medicines and Pharmaceutical Sciences, University of Lisbon, Portugal. rcastro@ff.ul.pt
Rita
R
Castro
Madalena
M
Barroso
Mónica
M
Rocha
Ruben
R
Esse
Ruben
R
Ramos
Paula
P
Ravasco
Isabel
I
Rivera
Isabel Tavares
IT
de Almeida
D000328:Adult; D005260:Female; D005492:Folic Acid / Q000378:metabolism; D005838:Genotype; D006710:Homocysteine / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000235:genetics*; D014155:Transcobalamins / Q000235:genetics*; D014805:Vitamin B 12 / Q000378:metabolism*
D014155:Transcobalamins; D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12