title: First-trimester ADAM12s as early markers of trisomy 21: a promise still unfulfilled?
abstract: BACKGROUND
  Here we study the levels of ADAM12s prior to and after 10 weeks of gestation to establish further the effectiveness or otherwise of ADAM12s as an early screening marker.
  
  
  METHODS
  Samples collected as part of routine first-trimester screening were retrieved from storage at - 80 degrees C. In total, 55 samples from pregnancies with trisomy 21 were identified, 31 collected between the 6th and 9th weeks of gestation and 24 collected after the 10th week. A series of 567 gestational age-matched samples collected during the same period formed the control group.
  
  
  RESULTS
  The median, multiples of the median (MoM) ADAM12s, at a median gestation of 10.0 weeks was 0.66, which was significantly lower than in the controls (p = < 0.001) when compared by Mann-Whitney test. The median MoM in those cases (n = 31) collected prior to 10 weeks was 0.618 MoM at a median gestation of 9.1 weeks. In those collected prior to 9 weeks (n = 14) the median was 0.596 at a median gestation of 8.6 weeks.
  
  
  CONCLUSIONS
  The data from this study does not support data from a previous study showing ultra-low levels of ADAM12s in pregnancies affected by trisomy 21 prior to 10 weeks of gestation.
authors.affiliation: Prenatal Screening Unit, Department of Clinical Biochemistry, King George Hospital, Barley Lane, 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: Niels
authors.initials: N
authors.lastname: Uldbjerg
authors.forename: Niels
authors.initials: N
authors.lastname: Tørring
mesh_terms: D051722:ADAM Proteins / Q000097:blood*; D000072199:ADAM12 Protein; D000328:Adult; D015415:Biomarkers / Q000097:blood; D004314:Down Syndrome / Q000097:blood* / Q000175:diagnosis*; D042241:Early Diagnosis; D005260:Female; D005865:Gestational Age; D006801:Humans; D008565:Membrane Proteins / Q000097:blood*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First / Q000097:blood*; D011296:Prenatal Diagnosis / Q000379:methods
chemical_list: D015415:Biomarkers; D008565:Membrane Proteins; D051722:ADAM Proteins; D000072199:ADAM12 Protein; C000606480:ADAM12 protein, human