Pyridoxine-related metabolite concentrations in normal and Down syndrome amniotic fluid.

INTRODUCTION Some studies of children with Down syndrome have found mild abnormalities in the metabolism of pyridoxine (vitamin B(6)); therefore the present question is whether such abnormalities might also be present in the amniotic fluid of fetuses with Down syndrome. MATERIALS AND METHODS Archived specimens of amniotic fluid were obtained from chromosomally normal and from fetuses with Down syndrome. Gas chromatography/mass spectrometry quantitized B-related metabolites, including oxalate, xanthurenate, kynurenine and 4-pyridoxic acid. RESULTS Oxalate, a marker of pyridoxine deficiency, was elevated in the amniotic fluid of fetuses with Down syndrome. This result was statistically significant. The other marker results were not statistically significant. CONCLUSION A marker of pyridoxine deficiency, oxalate is elevated in the amniotic fluid of fetuses with Down syndrome. These results in amniotic fluid are consistent with previous studies done in the urine of young children.