Spencer Spencer K K Bindra Bindra R R Nicolaides Nicolaides KH KH Maternal weight correction of maternal serum PAPP-A and free beta-hCG MoM when screening for trisomy 21 in the first trimester of pregnancy Maternal weight correction of maternal serum PAPP-A and free beta-hCG MoM when screening for trisomy 21 in the first trimester of pregnancy Prenat Diagn Prenat Diagn 2003 2003 23 23 851 851 5 5 10.1002/pd.708 10.1002/pd.708 14558032 14558032. The gene discussed is PAPPA; the disease is trisomy 21.