The level of ADAM12-S in maternal serum is an early first-trimester marker of fetal trisomy 18

Background ADAM12‐S is a pregnancy‐associated insulin‐like growth factor binding protein‐3 (IGFBP‐3) and IGFBP‐5 protease present in human gestational serum. Recently, maternal serum levels of ADAM12‐S were found to be markedly reduced during the first trimester of pregnancies with a Down syndrome (DS) fetus. On the basis of this finding, it was suggested that ADAM12‐S might be a useful maternal serum marker of fetal chromosomal disease. Objective Retrospective examination of the use of ADAM12‐S as a marker for fetal trisomy 18. Method Serum samples were obtained from ten women during the first semester of their pregnancies with fetuses that had trisomy 18. An ELISA was used to determine the levels of ADAM12 in maternal serum. Results were compared to ADAM12‐S levels, previously measured in the serum of 170 women carrying normal pregnancies during the first trimester. Results In all cases, the ADAM12‐S concentration in maternal serum samples was lower in trisomy 18 pregnancies than in normal pregnancies, with a median multiple of the median (MoM) of 0.28 (p < 0.001) Conclusion A reduced concentration of ADAM12‐S in maternal serum is a promising marker for foetal trisomy 18, as well as for DS. Copyright © 2005 John Wiley & Sons, Ltd.