title: Replicate real-time PCR testing of DNA in maternal plasma increases the sensitivity of non-invasive fetal sex determination.
abstract: BACKGROUND
  We determined fetal sex in pregnancies referred for invasive prenatal diagnosis procedures by analysis of DNA in maternal plasma.
  
  
  METHODS
  Twelve pregnancies at risk of X-linked haemophilia and 32 pregnancies at risk of chromosomal aneuploidies at a gestational age ranging from 10 to 18 weeks recruited before chorionic villus sampling or amniocentesis were involved in the study. Male fetal DNA in maternal plasma was detected by using real-time polymerase chain reaction with the SRY gene as a marker.
  
  
  RESULTS
  The specificity of the system reached 100% (no Y signal was detected in 17 women pregnant with a female fetus) and the sensitivity reached 100% (SRY amplification in 27 examined samples).
  
  
  CONCLUSIONS
  Amplification of free fetal DNA in maternal plasma is a valid and rapid technique for predicting fetal sex in first- and second-trimester pregnancies and could allow the restriction of invasive sampling procedures to male fetuses at risk of X-linked disorders.
authors.affiliation: 2nd Department of Paediatrics, 2nd Medical Faculty, Charles University, University Hospital Motol, V Uvalu 84, 150-18 Prague 5, Czech Republic. ilona.hromadnikova@lfmotol.cuni.cz
authors.forename: Ilona
authors.initials: I
authors.lastname: Hromadnikova
authors.forename: Bela
authors.initials: B
authors.lastname: Houbova
authors.forename: Dana
authors.initials: D
authors.lastname: Hridelova
authors.forename: Sona
authors.initials: S
authors.lastname: Voslarova
authors.forename: Josef
authors.initials: J
authors.lastname: Kofer
authors.forename: Vladimir
authors.initials: V
authors.lastname: Komrska
authors.forename: David
authors.initials: D
authors.lastname: Habart
mesh_terms: D000782:Aneuploidy; D041321:Chromosomes, Human, X; D004247:DNA / Q000097:blood*; D005260:Female; D024282:Genes, sry / Q000235:genetics; D008040:Genetic Linkage; D005865:Gestational Age; D006467:Hemophilia A / Q000235:genetics; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods*; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012680:Sensitivity and Specificity; D012732:Sex Determination Analysis / Q000379:methods*
chemical_list: D004247:DNA