title: [Non invasive detection of fetal Rh using real-time PCR method].
abstract: BACKGROUND
  In the last ten years the detection of fetal origin cells and cell free fetal DNA in maternal circulation opened new horizons in non-invasive prenatal diagnosis. The diagnostic possibilities are based on the differences between the maternal and fetal origin DNA. One of the differences could be the Rh blood group and the genetical background. The Rh incompatibility is the most frequent blood group incompatibilities in the clinical practice, which can cause fetal anemia, hydrops and even fetal death.
  
  
  OBJECTIVE
  The aim of this study was to detect the fetal DNA in maternal circulation, to determine the Rh status of the fetus, and to compare the reliability of the method with the data found in other studies.
  
  
  METHODS
  Blood samples and amnionic fluid samples were collected from 30 pregnant women, with Rh negative status, between 11-22 week of gestation presented for genetic amniocentesis at the 1st. Department of Obstetrics and Gynecology, Semmelweis University. After DNA isolation real-time PCR was performed in order to detect the exon 7 of the RhD gene located on the first chromosome (1p36.11.).
  
  
  RESULTS
  In 24 cases the PCR reaction gave same result in case of the DNA isolated from plasma and amniotic fluid, but in six cases there was no PCR product of plasma samples and the product was detectable in amniotic fluid samples. The exon 7 was detectable in 25 cases, and there was no product in 5 cases.
  
  
  CONCLUSIONS
  The real-time PCR method seems to be an easy and reliable method to determine the fetal Rh blood group. The sensitivity and specificity of the method in this study is in concordance with international data. The use of more than one probe could increase the sensitivity of the method.
authors.affiliation: Semmelweis Egyetem, Altalános Orvostudományi Kar I. Szülészeti és Nogyógyászati Klinika, Budapest. lazar_levente@hotmail.com
authors.forename: Levente
authors.initials: L
authors.lastname: Lázár
authors.forename: Bálint
authors.initials: B
authors.lastname: Nagy
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Bán
authors.forename: Gyula Richárd
authors.initials: GR
authors.lastname: Nagy
authors.forename: Artúr
authors.initials: A
authors.lastname: Beke
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Papp
mesh_terms: D000653:Amniotic Fluid / Q000276:immunology*; D002878:Chromosomes, Human, Pair 1; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D015342:DNA Probes; D005091:Exons; D005260:Female; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis / Q000379:methods*; D015203:Reproducibility of Results; D012203:Rh Isoimmunization / Q000175:diagnosis* / Q000235:genetics; D012680:Sensitivity and Specificity
chemical_list: D015342:DNA Probes; D004247:DNA