title: A rare de novo duplication of chromosome 21q22.12 → q22.3 with other concomitant deletion and duplication of small fragments in 21q associated with Down syndrome: Prenatal diagnosis, molecular cytogenetic characterization.
abstract: BACKGROUND
  Karyotyping is considered the gold standard for the genome-wide detection of genomic imbalances in prenatal diagnosis, but it has a number of inherent limitations, namely the time required to culture cell and the limited resolution(5 ~ 10 Mb). Although fluorescence in situ hybridization (FISH) can also be used as a rapid prenatal diagnosis for common aneuploidies, it is labor intensive, requires prior knowledge of the regions of interest, and can only be used to diagnose one or a few genomic regions simultaneously. Array comparative genomic hybridization (aCGH) can overcome the resolution, the locus-specific, and the time limitations of the karyotyping and FISH techniques and is currently the most powerful method for detecting chromosomal alterations in pre and postnatal clinical cases. Several investigations have suggested that the aCGH testing should be considered a first-tier test for the diagnosis of cytogenetic aberrations in the fetus.
  
  
  RESULTS
  This study used karyotyping, FISH, sequence-tagged site (STS) analysis and aCGH to diagnose a case of de novo duplication of chromosome 21q22.12 → q22.3 with other concomitant deletion and duplication of small fragments in 21q associated with Down syndrome prenatally.
  
  
  CONCLUSIONS
  FISH, aCGH and STS analysis are useful in prenatal investigation of the nature of de novo alterations of small fragments of the chromosome.
authors.affiliation: Department of Obstetrics & Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Peking Union Medical College, Dongdan, Dongcheng District, Beijing, 100730, P, R, China. qiqingwei@163.com.
authors.forename: Qingwei
authors.initials: Q
authors.lastname: Qi
authors.forename: Xiya
authors.initials: X
authors.lastname: Zhou
authors.forename: Yulin
authors.initials: Y
authors.lastname: Jiang
authors.forename: Na
authors.initials: N
authors.lastname: Hao
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang