title: Non-invasive prenatal diagnosis of trisomy 21 by reverse transcriptase multiplex ligation-dependent probe amplification.
abstract: BACKGROUND
  Obtaining fetal DNA or RNA by either chorionic villus sampling (CVS) or amniocentesis is currently, the gold standard prenatal diagnosis. However, these invasive procedures carry risk of miscarriage. A reliable method for non-invasive prenatal diagnosis (NIPD) has long been sought to reduce the risk of miscarriage.
  
  
  METHODS
  Cell-free fetal RNA was extracted from the plasma of peripheral blood from 121 women 9-20 weeks of pregnancy. Five single nucleotide polymorphism (SNP) loci in PLAC4 gene were analyzed by reverse transcriptase multiplex ligation-dependent probe amplification (RT-MLPA), followed by capillary electrophoresis. Karyotype analysis was used for confirmation of prenatal diagnosis of trisomy 21.
  
  
  RESULTS
  Of 121 samples, 23 were diagnosed with trisomy 21, 87 with normal ploidy, nine had all five SNP loci homozygous and two had one heterozygous SNP locus. Comparing with karyotype analysis, the diagnostic sensitivity and specificity of RT-MLPA were 92% and 100%, respectively.
  
  
  CONCLUSIONS
  RT-MLPA is a convenient and reliable method for the diagnosis of trisomy 21. We have shown that this method has good specificity, high sensitivity, and high throughput, making this technique applicable for NIPD in clinical practice.
authors.affiliation: Daan Gene Diagnostic Center, Sun Yet-Sen University, Guangzhou, Guangdong, PR China.
authors.forename: Yan-Hua
authors.initials: YH
authors.lastname: Deng
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Yin
authors.forename: Qiong
authors.initials: Q
authors.lastname: He
authors.forename: Jia-Chang
authors.initials: JC
authors.lastname: Chen
authors.forename: Yun-Shao
authors.initials: YS
authors.lastname: He
authors.forename: Hua-Qiao
authors.initials: HQ
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Hua-Yun
authors.initials: HY
authors.lastname: Chen
mesh_terms: D002474:Cell-Free System; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics*; D005260:Female; D005333:Fetus / Q000378:metabolism; D005787:Gene Frequency / Q000235:genetics; D056426:Genetic Loci / Q000235:genetics; D006801:Humans; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D015345:Oligonucleotide Probes / Q000235:genetics* / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics; D011296:Prenatal Diagnosis / Q000379:methods*; D012313:RNA / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism*
chemical_list: D015345:Oligonucleotide Probes; D011257:Pregnancy Proteins; D012313:RNA; D012194:RNA-Directed DNA Polymerase