MTHFR polymorphisms and serum cobalamin affect plasma homocysteine concentrations differentially in females and males

Abstract

A total of 523 subjects (297 females and 226 males) from the Canary Islands Nutrition Study (ENCA) were studied in order to examine the effect of the MTHFR 677C>T, 1298A>C and 1793G>A polymorphisms, adjusted for age, serum (5)-folate and S-cobalamin levels, on total plasma homocysteine concentrations (tHcy). Genotyping was performed with Pyrosequencing(R) technology. The MTHFR 677T-allele was associated with increased tHcy concentrations only in males (P=0.005). The MTHFR 1298C-allele was found to be associated with higher tHcy levels but similarly, only in males (P=0.025). The MTHFR 1793A-allele was associated with decreased tHcy concentrations in the younger males (P=0.042). A haplotype-based approach was marginally superior in explaining the genetic interaction of the MTHFR polymorphisms on tHcy plasma levels (R-2 0.352 vs. 0.342 for a simple genotype-based approach). A nutrigenetic interaction between the MTHFR 677C>T genotype and S-cobalamin on tHcy levels was demonstrated in both genders. The increase in tHcy was more pronounced with decreasing S-cobalamin quintiles in 677TT homozygotes (P=0.005 for males and P=0.015 for females) than with decreasing S-folate quintiles (P for trend not significant). It was concluded that gene-nutrient interactions may differ depending on the sex and age of the subjects. The transferability of gene-nutrient interactions from one community to others may therefore be limited not only by different food patterns but also by different ages, genders and genotype distributions.