JBRA Assist. Reprod. 2025;29(Suppl 1):21-21
POSTER PRESENTATION
doi: 10.5935/1518-0557.20250076
1Yikon Genomics Company, Ltd., Suzhou, China
2Yikon Genomics, S.L. Unipersonal., Barcelona, Spain
Objective: Preimplantation Genetic Testing for Aneuploidy (PGT-A) is a crucial tool in assisted reproductive technologies, aiming to improve implantation rates and reduce the risk of miscarriage by selecting euploid embryos for transfer. However, traditional PGT-A has limitations in detecting smaller copy number variations (CNVs) and uniparental disomies (UPD). This study aims to evaluate the efficacy of an expanded PGT-A protocol, termed PGT-A upgrade, in identifying not only aneuploidies but also UPD, microdeletions, and microduplications in embryos.
Methods: We employed a haplotype-aware inference approach with a dataset threshold of 3M NGS reads to perform PGT-A upgrade. This method reports CNVs above 4Mb and extends the analysis to include smaller CNVs in the range of 1-4Mb, providing a comprehensive assessment of embryonic genetic status. A retrospective analysis was conducted on 4300 embryos that underwent PGT-A upgrade to evaluate the detection rates of euploidy, UPD, and other genetic abnormalities.
Results: The euploidy rate among the 4300 embryos was 49.0%. The detection rates for UPD and triploidy were 0.11% (5/4300) and 0.22% (10/4300), respectively. Among the euploid embryos, 1.09% (23/2107) were found to carry small CNVs of 1-4Mb. To validate these findings, fluorescence in situ hybridization (FISH) was used to confirm the presence of these small CNVs in 22 cases, demonstrating a high concordance with the PGT-A upgrade results.
Conclusion: The PGT-A upgrade significantly enhances the detection capabilities of PGT-A by identifying not only larger CNVs but also smaller genetic anomalies that may impact embryonic development and pregnancy outcomes. This study highlights the importance of comprehensive genetic screening in preimplantation embryos, offering a deeper understanding of embryonic genetic health and potentially improving the success rates of assisted reproductive technologies.