ADAM12 is an effective marker in the second trimester of pregnancy for prenatal screening of Down syndrome.

Objective: To estimate the use of maternal serum ADAM12 as a second-trimester Down syndrome serum marker.

Methods: Samples from a total of 46 Down syndrome pregnancies and 184 unaffected singleton pregnancies matched for gestational age and maternal weight were retrieved from storage and measured for ADAM12; 35 false-positive pregnancies were included among the controls to assess reductions in false-positive rates by inclusion of ADAM12 in the risk calculation of an algorithm that used alpha-fetoprotein (AFP) and human chorionic gonadotrophin (hCG) (double screen).

Results: ADAM12 was measured and expressed as multiple of the gestation-specific median (MoM) and corrected for maternal weight. The median ADAM12 level in the affected pregnancies was 1.26 MoM compared with 1.0 MoM in the unaffected control pregnancies (p < 0.05). In unaffected pregnancies, there was a significant correlation between ADAM12 and AFP (r = 0.314) but not hCG (r = 0.018). Statistical modeling predicted that ADAM12 as a second serum marker could increase the detection rate from 48 to 85%, while reducing the false-negative and false-positive rates.

Conclusion: ADAM12 can be used as an effective second-trimester serum marker for prenatal screening of Down syndrome.