Plasma homocysteine association with vitamin B12 and folate status in young women with combined polymorphisms of the methylenetetrahydrofolate reductase gene
Bailey, L.B.; Duhaney, R.; Kauwell, G.P.A.; Maneval, D.; Hutson, A.; Davis, S.; Quinlivan, E.P.; Gregory, J.F.
FASEB Journal 16(4): A268
The influence of two MTHFR polymorphisms (C677T/A1298C) and the effect of serum B12 and folate (SF) concentrations on plasma homocysteine (Hcy) in women (n=186; 20-30 yr) was studied. Hcy was higher (p<0.05) in the homozygous/wild (TT/AA) group (n=23) relative to the other 5 genotypes including those doubly heterozygous (CT/AC) (n=32). Based on regression analysis, significant differences were detected in predicted mean Hcy as a function of the C677T (p=0.017) and A1298C (p=0.024) polymorphisms. Hcy was negatively associated with B12 (p=0.001) and SF (p=0.049), with the degree of correlation between B12 and Hcy dependent on genotype. Hcy decreased as B12 increased (p=0.0005) in doubly heterozygous (CT/AC) subjects with a similar trend in the homozygous/wild (TT/AA) and wild/homozygous (CC/CC) groups. In contrast, within the wild/wild (CC/AA) group, Hcy was not associated with changes in B12 concentrations. These data suggest that enhancing vitamin B12 status may significantly modulate Hcy in individuals doubly heterozygous or homozygous for either the C677T or A1298C MTHFR polymorphisms, even when B12 concentrations are in the normal range.