title: A new non-invasive prenatal diagnosis of Down syndrome through epigenetic markers and real-time qPCR.
abstract: BACKGROUND
  Non-invasive prenatal diagnosis (NIPD) of Down syndrome is rapidly evolving. Currently, two applications for NIPD of Down syndrome have been developed with potential and have displayed positive results; the NIPD using next-generation sequencing technologies and the NIPD using the methylated DNA immunoprecipitation (MeDIP) real-time quantitative polymerase chain reaction (qPCR).
  
  
  METHODS
  The MeDIP real-time qPCR approach is based on the identification of differentially methylated regions (DMRs) and their use for discriminating normal from Down syndrome cases. DMRs were identified using high-resolution oligo-arrays. A subgroup of DMRs was selected for further investigation. Through the design of a discriminant equation which combines the results obtained from different DMRs, normal and abnormal cases are correctly classified indicating 100% sensitivity and specificity.
  
  
  CONCLUSIONS
  Previous studies have also identified DMRs between non-pregnant female blood and placental DNA. However, these methods have been associated with a number of limitations including the low sensitivity and/or specificity of the assays, the limited number of identified DMRs or methylation sensitive sites and SNPs located on DMRs. These limitations have been overawed by the development of the MeDIP real-time qPCR-based methodology.
authors.affiliation: The Cyprus Institute of Neurology and Genetics, PO Box 23462, 1683, Nicosia, Cyprus. patsalis@cing.ac.cy
authors.forename: Philippos C
authors.initials: PC
authors.lastname: Patsalis
authors.forename: Evdokia
authors.initials: E
authors.lastname: Tsaliki
authors.forename: George
authors.initials: G
authors.lastname: Koumbaris
authors.forename: Alex
authors.initials: A
authors.lastname: Karagrigoriou
authors.forename: Voula
authors.initials: V
authors.lastname: Velissariou
authors.forename: Elisavet A
authors.initials: EA
authors.lastname: Papageorgiou
mesh_terms: D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics; D044127:Epigenesis, Genetic; D006801:Humans; D011296:Prenatal Diagnosis; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity