title: The detection of mosaicism by prenatal BoBs™.
abstract: OBJECTIVE
  The objective of the study was to evaluate the ability of a new prenatal diagnostic platform - prenatal BACs-on-Beads™ (BoBs™) in detecting mosaicism by comparison to quantitative fluorescence-polymerase chain reaction (QF-PCR).
  
  
  METHODS
  A validation study of prenatal BoBs™ was firstly performed using 18 artificially constructing mosaic samples involving various aneuploidies and microdeletion conditions. Additionally, we compared the accuracy between prenatal BoBs™ and QF-PCR for 18 archived clinical mosaic cases and nine chromosomally abnormal cell lines with reference to conventional karyotype results.
  
  
  RESULTS
  In the validation study, BoBs™ allowed the detection of mosaicism at a level of 20-40%. Among the clinical mosaic cases, 14/18 cases were within the detection of BoBs™, 8/14 (57.1%) could be identified by BoBs™ and 6/9 (66.7%) by QF-PCR, but 6/14 (42.9%) were missed by both tests. Three cases (16.7%) were detected by prenatal BoBs™ but missed by QF-PCR, whereas QF-PCR detected one case that was missed by BoBs™. The overall sensitivity of BoBs™ in detecting mosaicism is 44.4% (8/18), which is slightly higher than that of QF-PCR (33.3%; 6/18).
  
  
  CONCLUSIONS
  Prenatal BoBs™ has a sensitivity of 57.1% in the detection clinical mosaic cases. According to the validation test, mosaicism of 20% or greater is detectable by the BoBs™ assay.
authors.affiliation: Department of Obstetrics and Gynaecology, Prince of Wales Hospital, Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
authors.forename: Yvonne K Y
authors.initials: YK
authors.lastname: Cheng
authors.forename: Cherry
authors.initials: C
authors.lastname: Wong
authors.forename: Hoi Kin
authors.initials: HK
authors.lastname: Wong
authors.forename: Kwok On
authors.initials: KO
authors.lastname: Leung
authors.forename: Yvonne K
authors.initials: YK
authors.lastname: Kwok
authors.forename: Andy
authors.initials: A
authors.lastname: Suen
authors.forename: Chi Chui
authors.initials: CC
authors.lastname: Wang
authors.forename: Tak Yeung
authors.initials: TY
authors.lastname: Leung
authors.forename: Kwong Wai
authors.initials: KW
authors.lastname: Choy
mesh_terms: D000782:Aneuploidy; D025063:Chromosome Disorders / Q000196:embryology / Q000235:genetics*; D022202:Chromosomes, Artificial, Bacterial; D005260:Female; D006801:Humans; D007621:Karyotyping; D008863:Microspheres; D009030:Mosaicism / Q000196:embryology; D016133:Polymerase Chain Reaction / Q000379:methods; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity