Elevated plasma total homocysteine and C677T mutation of the methylenetetrahydrofolate reductase gene in patients with spina bifida

Total plasma homocysteine (tHcy) was significantly higher in 28 childrenwith spina bifida (median 6.05 mumol/l) as compared with 76 controls(median 4.94 mumol/l). This difference was confined to a subgroup ofpatients (16/28) with one or two C677T-mutated alleles in themethylenetetrahydrofolate reductase gene. Since we found no significantdifference between patients and controls in serum folate, erythrocytefolate, serum cobalamin or serum methylmalonic acid, which were within thenormal range for both patients and controls, the elevated tHcy could not beattributed to vitamin deficiencies. Our findings point to an additionalgenetic defect involving folate- dependent enzymes in a subgroup ofpatients with neural-tube defects.