title: Polar body array CGH for prediction of the status of the corresponding oocyte. Part I: clinical results.
abstract: BACKGROUND
  Several randomized controlled trials have not shown a benefit from preimplantation genetic screening (PGS) biopsy of cleavage-stage embryos and assessment of up to 10 chromosomes for aneuploidy. Therefore, a proof-of-principle study was planned to determine the reliability of alternative form of PGS, i.e. PGS by polar body (PB) biopsy, with whole genome amplification and microarray-based comparative genomic hybridization (array CGH) analysis.
  
  
  METHODS
  In two centres, all mature metaphase II oocytes from patients who consented to the study were fertilized by ICSI. The first and second PBs (PB1and PB2) were biopsied and analysed separately for chromosome copy number by array CGH. If either or both of the PBs were found to be aneuploid, the corresponding zygote was then also processed by array CGH for concordance analysis.
  
  
  RESULTS
  Both PBs were biopsied from a total of 226 zygotes from 42 cycles (average 5.5 per cycle; range 1-15) in 41 couples with an average maternal age of 40.0 years. Of these, the ploidy status of the zygote could be predicted in 195 (86%): 55 were euploid (28%) and 140 were aneuploid (72%). With only one exception, there was at least one predicted aneuploid zygote in each cycle and in 19 out of 42 cycles (45%), all zygotes were predicted to be aneuploid. Fresh embryos were transferred in the remaining 23 cycles (55%), and one frozen transfer was done. Eight patients had a clinical pregnancy of which seven were evolutive (ongoing pregnancy rates: 17% per cycle and 30% per transfer). The ploidy status of 156 zygotes was successfully analysed by array CGH: 38 (24%) were euploid and 118 (76%) were aneuploid. In 138 cases complete information was available on both PBs and the corresponding zygotes. In 130 (94%), the ploidy status of the zygote was concordant with the ploidy status of the PBs and in 8 (6%), the results were discordant.
  
  
  CONCLUSIONS
  This proof-of-principle study indicates that the ploidy of the zygote can be predicted with acceptable accuracy by array CGH analysis of both PBs.
authors: Department of Genetics and Cell Biology, Research Institute GROW, Faculty of Health, Medicine and Life Sciences, Maastricht University, PO Box 5800, Maastricht, AZ 6202, The Netherlands. joep.geraedts@mumc.nl
authors: Joep
authors: J
authors: Geraedts
authors: Markus
authors: M
authors: Montag
authors: M Cristina
authors: MC
authors: Magli
authors: Sjoerd
authors: S
authors: Repping
authors: Alan
authors: A
authors: Handyside
authors: Catherine
authors: C
authors: Staessen
authors: Joyce
authors: J
authors: Harper
authors: Andreas
authors: A
authors: Schmutzler
authors: John
authors: J
authors: Collins
authors: Veerle
authors: V
authors: Goossens
authors: Hans
authors: H
authors: van der Ven
authors: Katerina
authors: K
authors: Vesela
authors: Luca
authors: L
authors: Gianaroli
mesh_terms: D000328:Adult; D001706:Biopsy / Q000379:methods; D002875:Chromosomes; D022202:Chromosomes, Artificial, Bacterial; D055028:Comparative Genomic Hybridization / Q000379:methods*; D004624:Embryo Transfer; D005060:Europe; D005260:Female; D006801:Humans; D008297:Male; D008423:Maternal Age; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D009865:Oocytes / Q000166:cytology*; D011003:Ploidies; D059705:Polar Bodies / Q000166:cytology*; D011247:Pregnancy; D018873:Pregnancy Rate; D019836:Preimplantation Diagnosis / Q000379:methods; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods*