title: Total cell-free DNA (beta-globin gene) distribution in maternal plasma at the second trimester: a new prospective for preeclampsia screening.
abstract: OBJECTIVE
  Levels of cell-free foetal DNA (f-DNA) in maternal plasma are higher in those asymptomatic subjects who will eventually develop preeclampsia. f-DNA is, however, informative only for those women bearing a male foetus, by amplification of Y-specific sequences and represents a small fraction of total circulating DNA that can be dosed by using ubiquitous genes as well as beta-globin. In this study, we examined the quantitative distribution of total DNA by amplification of beta-globin gene, in asymptomatic women matched with controls to evaluate its possible role in predicting preeclampsia.
  
  
  METHODS
  Forty-eight low-risk women (8 asymptomatic cases matched for gestational age at the second trimester with 40 controls) were enrolled in the present study. beta-globin concentrations were converted into multiples of the median of the controls (MoM), in order to assess the possible different distribution of beta-globin MoM in cases and controls.
  
  
  RESULTS
  MoM values were as follows: controls, 1.00 +/- 0.59; asymptomatic cases, 1.99 +/- 1.95. After Gaussian conversion of data, at a false-positive rate (FPR) of 5%, the detection rate (DR) was 46%.
  
  
  CONCLUSIONS
  beta-globin (total DNA) levels are higher in those patients who subsequently developed preeclampsia and can potentially be used in screening for early detection of the disease. These findings represent a step forward in the study of cell-free DNA in maternal blood as a screening variable, because it overcomes the gender limitations of foetal DNA screening.
authors.affiliation: Department of Obstetrics and Gynaecology, Showa University School of Medicine, Tokyo, Japan. antonio.farina@unibo.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Farina
authors.forename: Akihiko
authors.initials: A
authors.lastname: Sekizawa
authors.forename: Mariko
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Ryu
authors.initials: R
authors.lastname: Matsuoka
authors.forename: Kiyotake
authors.initials: K
authors.lastname: Ichizuka
authors.forename: Takashi
authors.initials: T
authors.lastname: Okai
mesh_terms: D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D004247:DNA / Q000097:blood*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005914:Globins / Q000032:analysis* / Q000235:genetics; D006801:Humans; D008431:Maternal-Fetal Exchange; D011225:Pre-Eclampsia / Q000097:blood / Q000175:diagnosis*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis / Q000379:methods*
chemical_list: D015415:Biomarkers; D005914:Globins; D004247:DNA