title: Discordance among blastomeres renders preimplantation genetic diagnosis for aneuploidy ineffective.
abstract: OBJECTIVE
  To investigate the contribution of discordance among blastomeres from the same embryo in the interpretation of blastomeres biopsied from day 3 embryos.
  
  
  METHODS
  228 IVF embryos had two blastomeres removed and fluorescent in situ hybridization (FISH) was used to detect aneuploidy of chromosomes 13, 15, 16, 18, 21, 22, X and Y. Of the 228 embryos, 102 had complete FISH results for both blastomeres.
  
  
  RESULTS
  When the 2 blastomeres of 102 embryos with successful FISH results were compared, 26 (25.5%) were concordant for all 8 chromosomes and 76 (74.5%) were discordant for one or more chromosomes. Among the 102 embryos, 12 (12%) were disomy in both blastomeres and 37 (36%) were disomic in all 8 chromosomes in one of the two blastomeres.
  
  
  CONCLUSIONS
  Discordance among blastomeres from the same embryo appears to present a significant problem in interpreting results of embryos biopsied on day 3 and analyzed by FISH especially when most PGD's are done on single blastomeres.
authors.affiliation: Pregnancy Success Center, Rinehart Center for Reproductive Medicine, 233 East Erie St, Suite 500, Chicago, IL 60611, USA. cbcoulam@aol.com
authors.forename: C B
authors.initials: CB
authors.lastname: Coulam
authors.forename: R S
authors.initials: RS
authors.lastname: Jeyendran
authors.forename: M
authors.initials: M
authors.lastname: Fiddler
authors.forename: E
authors.initials: E
authors.lastname: Pergament
mesh_terms: D000328:Adult; D000782:Aneuploidy; D001757:Blastomeres / Q000166:cytology*; D047108:Embryonic Development; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009030:Mosaicism; D011247:Pregnancy; D019836:Preimplantation Diagnosis / Q000379:methods*; D020554:Sperm Injections, Intracytoplasmic