title: Prenatal BACs-on-Beads™: the prospective experience of five prenatal diagnosis laboratories.
abstract: OBJECTIVE
  We previously reported on the validation of Prenatal BACs-on-Beads™ on retrospectively selected and prospective prenatal samples. This bead-based multiplex assay detects chromosome 13, 18, 21 and X/Y aneuploidies and the nine most frequent microdeletion syndromes. We demonstrated that Prenatal BACs-on-Beads(TM) is a new-generation, prenatal screening tool. Here, we describe the experience of five European prenatal diagnosis laboratories concerning the ongoing use of Prenatal BACs-on-Beads™ .
  
  
  METHODS
  Some 1653 samples were analyzed. All results were confirmed by conventional karyotyping or another appropriate technique. All indications for invasive prenatal diagnosis were included. Amniotic fluid and chorionic villus samples were analyzed in equivalent proportions.
  
  
  RESULTS
  The failure rate was 3.3% and the overall abnormality detection rate was ~1/10. Eighty-five percent of the detected abnormalities were common aneuploidies. Eleven microdeletions and duplications were identified, thus giving an overall yield for microdeletion and microduplication detection of 1/145. Compared with QF-PCR, Prenatal BACs-on-Beads™ provides an additional detection rate of ~1/250 for low-risk pregnancies. The false positive and negative rates were both <1%.
  
  
  CONCLUSIONS
  When associated with conventional karyotyping, the Prenatal BACs-on-Beads™ assay combines a short turnaround time (typical of rapid aneuploidy detection tests) with valuable detection of the most frequent microdeletion syndromes that cannot be detected in cytogenetic analyses.
authors.affiliation: Department of Cytogenetics, Obstetrics and Gynecology, CHI Poissy St Germain, Poissy, France. fvialard@hotmail.com
authors.forename: François
authors.initials: F
authors.lastname: Vialard
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Simoni
authors.forename: Denise Molina
authors.initials: DM
authors.lastname: Gomes
authors.forename: Azzedine
authors.initials: A
authors.lastname: Abourra
authors.forename: Simona
authors.initials: S
authors.lastname: De Toffol
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bru
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: Martinez Romero
authors.forename: Lucio
authors.initials: L
authors.lastname: Nitsch
authors.forename: Philippe
authors.initials: P
authors.lastname: Bouhanna
authors.forename: Livia
authors.initials: L
authors.lastname: Marcato
authors.forename: Thomas
authors.initials: T
authors.lastname: Popowski
authors.forename: Beatrice
authors.initials: B
authors.lastname: Grimi
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Martínez-Conejero
authors.forename: B
authors.initials: B
authors.lastname: Benzacken
authors.forename: Rita
authors.initials: R
authors.lastname: Genesio
authors.forename: Francesca R
authors.initials: FR
authors.lastname: Grati
mesh_terms: D000328:Adult; D000649:Amniocentesis / Q000379:methods*; D000653:Amniotic Fluid / Q000737:chemistry / Q000166:cytology*; D000782:Aneuploidy; D015193:Chorionic Villi Sampling / Q000379:methods*; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000235:genetics; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics*; D003951:Diagnostic Errors / Q000706:statistics & numerical data; D005240:Feasibility Studies; D005260:Female; D005312:Fetal Blood / Q000737:chemistry / Q000166:cytology; D005865:Gestational Age; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D025202:Molecular Diagnostic Techniques; D011247:Pregnancy; D011446:Prospective Studies; D015203:Reproducibility of Results; D012189:Retrospective Studies