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Updated: Jul 17, 2026

Semiconductor Sequencing for Preimplantation Genetic Testing for Aneuploidy
Published on: August 25, 2019
Discordance among blastomeres renders preimplantation genetic diagnosis for aneuploidy ineffective
C B Coulam1, R S Jeyendran, M Fiddler
1Pregnancy Success Center, Rinehart Center for Reproductive Medicine, 233 East Erie St, Suite 500, Chicago, IL 60611, USA. cbcoulam@aol.com
Purpose:
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.
Conclusion:
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.
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