title: MeDIP real-time qPCR of maternal peripheral blood reliably identifies trisomy 21.
abstract: OBJECTIVE
  To reevaluate the efficiency of the 12 differentially methylated regions (DMRs) used in the methylated DNA immunoprecipitation (MeDIP) real-time quantitative polymerase chain reaction (real-time qPCR) based approach, develop an improved version of the diagnostic formula and perform a larger validation study.
  
  
  METHODS
  Twelve selected DMRs were checked for copy number variants in the Database of Genomic Variants. The DMRs located within copy number variants were excluded from the analysis. One hundred and seventy-five maternal peripheral blood samples were used to reconstruct and evaluate the new diagnostic formula and for a larger-scale blinded validation study using MeDIP real-time qPCR.
  
  
  RESULTS
  Seven DMRs entered the final model of the prediction equation and a larger blinded validation study demonstrated 100% sensitivity and 99.2% specificity. No significant evidence for association was observed between cell free fetal DNA concentration and D value.
  
  
  CONCLUSIONS
  The MeDIP real-time qPCR method for noninvasive prenatal diagnosis of trisomy 21 was confirmed and revalidated in 175 samples with satisfactory results demonstrating that it is accurate and reproducible. We are currently working towards simplification of the method to make it more robust and therefore easily, accurately, and rapidly reproduced and adopted by other laboratories. Nevertheless, larger scale validation studies are necessary before the MeDIP real-time qPCR-based method could be applied in clinical practice.
authors: NIPD Genetics Ltd, Nicosia, Cyprus.
authors: Evdokia
authors: E
authors: Tsaliki
authors: Elisavet A
authors: EA
authors: Papageorgiou
authors: Christiana
authors: C
authors: Spyrou
authors: George
authors: G
authors: Koumbaris
authors: Elena
authors: E
authors: Kypri
authors: Skevi
authors: S
authors: Kyriakou
authors: Chrysovalanto
authors: C
authors: Sotiriou
authors: Evi
authors: E
authors: Touvana
authors: Anna
authors: A
authors: Keravnou
authors: Alex
authors: A
authors: Karagrigoriou
authors: Klea
authors: K
authors: Lamnissou
authors: Voula
authors: V
authors: Velissariou
authors: Philippos C
authors: PC
authors: Patsalis
mesh_terms: D000328:Adult; D004247:DNA / Q000097:blood*; D019175:DNA Methylation / Q000235:genetics*; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D005333:Fetus / Q000737:chemistry; D005865:Gestational Age; D006801:Humans; D007163:Immunosorbent Techniques; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D004247:DNA