title: Maternal serum ADAM12s in the late first trimester of pregnancies with Trisomy 21.
abstract: BACKGROUND
  ADAM12s is a placenta-derived glycoprotein that is involved in growth and differentiation, and has been shown to be a potential first-trimester and second-trimester marker of Trisomy 21 and other aneuploides. Maternal ADAM12s concentrations show a considerable temporal variation with gestational age and here we study the levels at 11-13 weeks of gestation to establish the effectiveness or otherwise at a time when other established markers are used.
  
  
  METHODS
  Samples collected as part of routine first-trimester screening were retrieved from storage. In total, 46 samples from pregnancies with Trisomy 21 were identified and collected between 11 and 13 weeks of gestation-of these 83% had been identified by combined first-trimester screening. A series of 414 gestational age-matched samples collected during the same period formed the control group. ADAM12s was measured by a new DELFIA assay incorporating two monoclonals (6E6 and 8F8). Results were expressed as weight-corrected multiples of the median (MoM).
  
  
  RESULTS
  The median MoM ADAM12s rose from 0.914 at 11 weeks to 1.032 at 13 weeks.
  
  
  CONCLUSIONS
  Combining the data from this study and other published studies suggests that ADAM12s is unlikely to be of much additional value when screening for Trisomy 21 in the period 11-13 weeks. More studies are required looking at the potential of ADAM12s prior to 10 weeks.
authors.affiliation: Prenatal Screening Unit, Clinical Biochemistry Department, King George Hospital, Goodmayes, Essex IG3 8YB, UK. KevinSpencer1@aol.com
authors.forename: Kevin
authors.initials: K
authors.lastname: Spencer
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Cowans
authors.forename: Anastasia
authors.initials: A
authors.lastname: Stamatopoulou
mesh_terms: D051722:ADAM Proteins / Q000097:blood*; D000072199:ADAM12 Protein; D015415:Biomarkers / Q000097:blood; D004314:Down Syndrome / Q000097:blood* / Q000175:diagnosis; D005260:Female; D006801:Humans; D008565:Membrane Proteins / Q000097:blood*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis
chemical_list: D015415:Biomarkers; D008565:Membrane Proteins; D051722:ADAM Proteins; D000072199:ADAM12 Protein; C000606480:ADAM12 protein, human