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 childr en with spina bifida (median 6.05 mu mol/l) as compared with 76 contro ls (median 4.94 mu-mol/l). This difference was confined to a subgroup of patients (16/28) with one or two C677T-mutated alleles in the methy lenetetrahydrofolate reductase gene. Since we found no significant dif ference between patients and controls in serum folate, erythrocyte fol ate, serum cobalamin or serum methylmalonic acid, which were within th e normal range for both patients and controls, the elevated tHcy could not be attributed to vitamin deficiencies. Our findings point to an a dditional genetic defect involving folate-dependent enzymes in a subgr oup of patients with neural-tube defects.