title: Rapid detection of Down's syndrome using quantitative real-time PCR (qPCR) targeting segmental duplications on chromosomes 21 and 11.
abstract: OBJECTIVE
  Development of a qPCR test for the detection of trisomy 21 using segmental duplications.
  
  
  METHODS
  Segmental duplications in the TTC3 gene on chromosome 21 and the KDM2A gene on chromosome 11 were selected as molecular markers for the diagnostic qPCR assay. A set of consensus primers selected from the conserved regions of these segmental duplications were used to amplify internal diverse sequences that were detected and quantified with different probes labeled with distinct fluorescence. The copy numbers of these two fragments were determined based on the ΔCq values of qPCR. The results of qPCR for prenatal and neonatal screening of Down's syndrome were compared with the conventional karyotype analysis by testing 82 normal individuals and 50 subjects with Down's syndrome.
  
  
  RESULTS
  The ΔCq values of segmental duplications on chr21 and 11 ranged between 0.33 and 0.75 in normal individuals, and between 0.91 and 1.18 in subjects with Down's syndrome. The ΔCq values of these two segmental duplications clearly discriminated Down's syndrome from normal individuals (P<0.001). Furthermore, the qPCR results were consistent with karyotype analysis.
  
  
  CONCLUSIONS
  Our qPCR can be used for rapid prenatal and neonatal screening of Down's syndrome.
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Hospital, Guangxi, China. Electronic address: sunshijie12345@163.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Hospital, Guangxi, China.
authors.forename: Zuqian
authors.initials: Z
authors.lastname: Fan
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Hospital, Guangxi, China.
authors.forename: Xunjin
authors.initials: X
authors.lastname: Weng
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Hospital, Guangxi, China.
authors.forename: Xuehe
authors.initials: X
authors.lastname: Ye
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Hospital, Guangxi, China.
authors.forename: Ju
authors.initials: J
authors.lastname: Long
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Hospital, Guangxi, China.
authors.forename: Kepeng
authors.initials: K
authors.lastname: Fu
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Hospital, Guangxi, China.
authors.forename: Shanhuo
authors.initials: S
authors.lastname: Yan
authors.affiliation: Genetics Laboratory, Hubei Maternal and Child Health Hospital, Hubei, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Hospital, Guangxi, China.
authors.forename: Yongguang
authors.initials: Y
authors.lastname: Zhuo
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Hospital, Guangxi, China.
authors.forename: Xinxing
authors.initials: X
authors.lastname: Liu
authors.affiliation: Laboratory of Medical Genetics, Qinzhou Maternal and Child Health Hospital, Guangxi, China.
authors.forename: Kegan
authors.initials: K
authors.lastname: Lao
mesh_terms: D001483:Base Sequence; D002880:Chromosomes, Human, Pair 11; D002891:Chromosomes, Human, Pair 21; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008969:Molecular Sequence Data; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods; D060888:Real-Time Polymerase Chain Reaction; D056916:Segmental Duplications, Genomic
keywords: Down's syndrome; Quantitative real-time PCR; Trisomy 21; ΔCq values