Incidental reports suggest that antenatal treatment of
pyridoxine dependent seizures (PDS) may improve neurodevelopmental outcome of affected patients. Two families with PDS are reported, both with two affected siblings. Antenatal treatment with
pyridoxine was instituted during the second pregnancy in each family (50 and 60 mg daily from 3 and 10 weeks of gestation, respectively). Perinatal characteristics and neurodevelopmental outcome at 4 (Family A) and 12 (Family B) years of age were compared between the untreated and treated child within each family. Meconium-stained amniotic fluid was present in both first pregnancies and abnormal foetal movements were noticed in one. In the treated infants, pregnancy and birth were uncomplicated. In family A, postnatal
pyridoxine supplementation prevented neonatal
seizures. Both children in family A were hypotonic and started walking after 2 years of age; both had white matter changes on MRI, and the first child was treated for
squint. IQ was 73 and 98 in the antenatally untreated and treated child, respectively. The second child in family B developed
seizures on the seventh day, because
pyridoxine maintenance
therapy had not been instituted after birth.
Seizures responded rapidly to
pyridoxine supplementation. MRI showed large ventricles and a mega cisterna magna. IQ was 80 and 106 in the antenatally untreated and treated child respectively. Both children had normal motor development. These results suggest that antenatal
pyridoxine supplementation may be effective in preventing intrauterine
seizures, decreasing the risk of complicated birth and improving neurodevelopmental outcome in PDS.