PLASMA HOMOCYSTEINE AND METHIONINE CONCENTRATIONS IN CHILDREN WITH NEURAL-TUBE DEFECTS

Mild to moderate homocysteinemia in women has been associated with an increased frequency of pregnancies with neural tube defects (NTD). Hom ocysteinemia is also an independent risk factor for premature vascular disease. In addition to folic acid, supplemental Vitamin B12, Vitamin B6 and betaine may normalize homocysteine metabolism, decrease the ri sk for NTD formation, and correct related metabolic imbalances in chil dren with NTD. By means of automated amino acid analysis, we assessed total non-fasting homocysteine and methionine in plasma from 24 childr en with myelomenin-gocele. This study group (mean age 10.5+/-4.9 years ) included 12 girls and 12 boys randomly selected from our Birth Defec ts Clinic. Homocysteine concentrations in our patients (4.7+/-1.8 mu m ol/L) did not differ from those of 20 randomly selected child controls (5.1+/-2.6 mu mol/L). The mean homocysteine concentration for 36 adul t controls (9.3+/-3.0 mu mol/L) was significantly higher than the mean for either group of children (p <0.0001). Linear regression analysis revealed negative correlation of total plasma homocysteine with serum folate (r=-0.53; p=0.01), but not of homocysteine with either methioni ne or B12. Plasma methionine concentrations from our patients did not differ from adult reference values. Elevated homocysteine in some moth ers of children with NTD has been attributed to defective methylation of homocysteine. These preliminary results do not indicate such a defe ct in the children themselves. A more comprehensive study of homocyste ine, methionine and related metabolites in children with NTD and age-m atched controls will be required to determine the clinical significanc e of these findings.