Metabolic effects of C677T and A1298C mutations at the MTHFR gene in Brazilian children with neural tube defects

Background: Methylenetetrahydrofolate reductase (MTHFR) deficiency leads to impairment in folate metabolism and is implicated as a risk factor for neural tube defects (NTDs). Both C677T and A1298C MTHFR mutations are associated with NTDs, in some populations. Methods: The frequencies of the C677T and A1298C MTHFR mutations were determined in 25 children with NTDs, case mothers and 75 healthy individuals from Sao Paulo City. Both C677T and A1298C mutations were analyzed by PCR-FLRP. The effects of MTHFR mutations on folate, vitamin B 12 and homocysteine concentrations were also evaluated. Results: C677T and A1298C allele frequencies in NTDs children and mothers were similar to that found in controls. Eleven in 23 NTDs patients and 10 in 21 NTDs mothers had folate or vitamin B12 concentrations in the lower end of the normal range. In NTDs children, C677T MTHFR genotypes did not affect vitamins and homocysteine concentrations, but plasma homocysteine was higher (p = 0.028) in patients with 1298AA MTHFR genotype. Moreover, 677CT/1298AA haplotype was associated with lower vitamin B12 concentrations (p < 0.05) in NTDs children. Conclusions: MTHFR gene mutations may affect vitamin B12 and homocysteine metabolism in Brazilian children with NTDs. (C) 2002 Elsevier Science B.V. All rights reserved.