Reanalyzing discarded blastocyst embryos for autosomal aneuploidy after sex selection in cleavage stage

Background: Pre-implantation genetic screening (PGS) is used to identify common chromosomal abnormality. Aneuploidy is a key genetic factor that can influence human reproductive success in ART. Moreover, existence of high rate of mosaicism in cleavage stage has been reported. In spite of rescue from aneuploidy in blastocyst, evaluation of chromosomal abnormality is crucial.Objective: Evaluation of autosomal aneuploidies in discarded embryos after sex selection which was received to the blastocyst stage.Materials and Methods: Thirty discarded embryos which were biopsied in cleavage stage and reached to blastocyst stage reanalyzed by fish method for 8 chromosomes: 13, 15, 16, 18, 21, 22, xy. These discarded embryos were resulted from PGS program for sex selection.Results: Although, it is expected that the rate of chromosomal abnormalities in the blastocyst stage would be reduced than cleavage stage. Our results were showed that a significant rate of autosomal aneuploidy in reanalyzed embryos which were reached to the blastocyst stage. Overall, the study of aneuploidies rate in the blastocyst stage indicated that 40% of the investigated blastocyst embryos had chromosomal abnormalities. Among the analyzed blastocyst for common 8 chromosomes, chromosome 13 have the highest rate of abnormality and aneuploidy in the other chromosomes ranged between 5-10%.Conclusion: Our results suggest that, to be appraised critical autosomal chromosomes in combined with sex chromosome in a PGS program for sex selection. These chromosomes have a predominant role in aneuploidies detected in recurrent abortions, IVF failure and disruption occurs in the term.

Keywords:

PGS , FISH , Trophoectoderm biopsy , ART