title: [Diagnosis of Down's syndrome using short tandem repeat loci D21S11, D21S1440 and Penta D].
abstract: OBJECTIVE
  To investigate the feasibility of genetic diagnosis of Down's syndrome (DS) using short tandem repeat (STR), and to develop a rapid and accurate method for diagnosing DS.
  
  
  METHODS
  Quantitative fluorescence polymerase chain reaction (QF-PCR) was used to amplify STR loci D21S11, D21S1440 and Penta D of 719 samples. Three hundred and eighty-nine samples were peripheral blood, 282 were amniotic fluid, 48 were chorionic villous samples. The products were analyzed using eleterophoresis to detect DS.
  
  
  RESULTS
  Among 652 samples with a normal karyotype, 635 showed 2 bands with a 1:1 ratio or a single band. The remaining 17 samples showed 3 bands, and were regarded as false positive results. For 67 DS samples, 53 showed 3 bands/peaks with a 1:1:1 ratio and 14 showed 2 bands/peaks with a 2:1 ratio. The sensitivity and specificity of STR loci D21S11, D21S1440 and Penta D were 76.12% and 98.62%, 71.64% and 98.93%, 89.55% and 99.85%, respectively. The overall sensitivity and specificity of 3 STR loci were 100% (67/67) and 97.39% (635/652), respectively.
  
  
  CONCLUSIONS
  Compared with conventional method, author's method is simpler, more stable and rapid, and can be used for large-scale prenatal screening of DS.
authors.affiliation: Department of Medical Genetics, Tianjin Medical University General Hospital, Tianjin, People's Republic of China.
authors.forename: Yun-fang
authors.initials: YF
authors.lastname: Shi
authors.forename: Xiao-zhou
authors.initials: XZ
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Xiu-ling
authors.initials: XL
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Tian-fu
authors.initials: TF
authors.lastname: Yue
mesh_terms: D000653:Amniotic Fluid / Q000737:chemistry; D002824:Chorionic Villi / Q000737:chemistry; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics*; D005260:Female; D006801:Humans; D018895:Microsatellite Repeats; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D012680:Sensitivity and Specificity