Aim: The aim of this study was to investigate possible relationships among the A1298C (rs1801131) and C677T (rs1801133) polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and levels of homocysteine, vitamins B₆, B₁₂, folic acid and lipid profile, including oxidized low-density lipoprotein (ox-LDL), of adolescents at cardiovascular risk. Methods: We recruited 115 adolescents (10-19 years old), 58.3% (n = 67) female, from a public school in Brazil who underwent anthropometric, biochemical and genetic tests as well as food consumption evaluation. Results: An important prevalence of hyperhomocysteinemia (19.1%) and alterations in triacylglycerol (17.4%), total cholesterol (26.9%) and high-density lipoprotein (HDL) cholesterol (48.0%) concentrations were observed, as well as low vitamin B₆ concentrations (23.5%). The categorization of homocysteine concentrations into tertiles revealed significant differences in serum concentrations of folate, vitamin B₁₂ and HDL, waist circumference and intake of total and saturated fat among the tertiles. The presence of variant alleles regarding the MTHFR C677T polymorphism interfered with vitamin B₆ and ox-LDL cholesterol concentrations. There was a trend for higher waist circumference values in T carriers (C677T), but not in C carriers (A1298C). Conclusions: The MTHFR C677T allele was associated with higher plasma vitamin B₆ and ox-LDL compared to the CC genotype.

Aim: The aim of this study was to investigate possible relationships among the A1298C (rs1801131) and C677T (rs1801133) polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and levels of homocysteine, vitamins B₆, B₁₂, folic acid and lipid profile, including oxidized low-density lipoprotein (ox-LDL), of adolescents at cardiovascular risk. Methods: We recruited 115 adolescents (10-19 years old), 58.3% (n = 67) female, from a public school in Brazil who underwent anthropometric, biochemical and genetic tests as well as food consumption evaluation. Results: An important prevalence of hyperhomocysteinemia (19.1%) and alterations in triacylglycerol (17.4%), total cholesterol (26.9%) and high-density lipoprotein (HDL) cholesterol (48.0%) concentrations were observed, as well as low vitamin B₆ concentrations (23.5%). The categorization of homocysteine concentrations into tertiles revealed significant differences in serum concentrations of folate, vitamin B₁₂ and HDL, waist circumference and intake of total and saturated fat among the tertiles. The presence of variant alleles regarding the MTHFR C677T polymorphism interfered with vitamin B₆ and ox-LDL cholesterol concentrations. There was a trend for higher waist circumference values in T carriers (C677T), but not in C carriers (A1298C). Conclusions: The MTHFR C677T allele was associated with higher plasma vitamin B₆ and ox-LDL compared to the CC genotype.