S100B content and SOD activity in amniotic fluid of pregnancies with Down syndrome

Objectives: We measured S100B levels and superoxide dismutase (SOD) activity retrospectively in amniotic fluid samples from pregnancies with normal and Down syndrome (DS) fetuses. Design and methods: Samples from 26 normal and 71 Down syndrome fetuses were studied. S100B protein levels were determined using LIA-mat Sangtec kit, and SOD activity was measured with the RANSOD kit. Results: We observed significantly higher levels of S100B in the Down group (median of 1.24 μg/l) than in the control group (median 0.69 μg/l). S100B concentration in DS samples increased from the 13th to the 18th week of gestation and was positively correlated with gestational age. The amniotic fluid SOD activity in the DS group (16.60 U/mg/prot) was significantly higher than in the normal one (10.78 U/mg/prot). Conclusions: This study indicates that S100B and SOD in amniotic fluid could be used as additional parameters for prenatal screening of trissomy 21 and that S100B values are associated with the gestational age.