Discordance among blastomeres renders preimplantation genetic diagnosis for aneuploidy ineffective.
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.
Coulam
C B
CB
Pregnancy Success Center, Rinehart Center for Reproductive Medicine, 233 East Erie St, Suite 500, Chicago, IL 60611, USA. cbcoulam@aol.com
Jeyendran
R S
RS
Fiddler
M
M
Pergament
E
E
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