Résumé
ObjectiveTo investigate the application of optical genome mapping （OGM） technology in detecting complex chromosomal rearrangement. MethodsWe recruited five patients who were diagnosed as complex chromosomal rearrangement at the Reproductive Medicine Center of the Sixth Affiliated Hospital of Sun Yat-sen University from January 2022 to June 2023. They underwent OGM， nanopore sequencing and pre-implantation genetic testing （PGT）. The results were compared with the results of karyotype and chromosomal microarray analysis （CMA）/ copy number variation sequencing （CNV-Seq）. ResultsOGM could detect translocation， invert inversion， and triplet translocation， which were consistent with the results of OGM and CMA/ CNV-Seq. But OGM could not detect Robertsonian translocation. ConclusionBecause of its ultra-long reads， OGM realizes the detection across repetitive regions， and it has great advantages when applied in patients with complex chromosome rearrangement or uncertain karyotype analysis. It can accurately locate breakpoints.
Résumé
Background@#Pre-implantation Genetic Testing for Aneuploidy (PGT-A) has enabled IVF specialists to screen embryos for abnormalities in chromosome number and structure. Subsequently, healthy embryos are selected for transfer, decreasing the rate of spontaneous miscarriages and improving pregnancy outcomes. In spite of this, almost only half of the PGTdetermined euploid embryos result in a pregnancy. @*Objective@#This study aimed to determine what other factors among euploid embryo transfers will have an association with successful implantation and live birth. @*Methods@#This study retrospectively analyzed 159 IVF-PGS cycles performed in CARMI SLMCGC from January 2017 to December 2019. Of these, a total of 231 euploid embryos (86 single embryo transfers and 73 double embryo transfers) were assessed. The relationship of eight predictive variables (maternal age, maternal BMI, etiology of infertility, history of failed IVF, blastocyst expansion stage, ICM grade, TE grade and endometrial thickness on transfer) with regard to the outcome of successful implantation and live birth among single or double euploid blastocyst transfers were determined via logistic regression analysis. @*Results@#Overall, the implantation rate was significantly lower when using B-grade ICM or C-grade ICM blastocysts as compared to A-grade ICM blastocysts (OR 0.54, 95% CI 0.356- 0.815, p = 0.003). With regard to live birth rate, the success of transfer is statistically lower when using a B-grade or C-grade ICM blastocysts as compared to A-grade ICM blastocysts (OR 0.55, CI 0.354-0.863, p = 0.009). Other predictive factors such as maternal age, maternal BMI, etiology of infertility, number of previous IVF, blastocyst expansion stage, trophectoderm grade and endometrial thickness had no apparent effect on the outcome of implantation and live birth. @*Conclusion@#Present study results suggest that only the ICM grade of euploid blastocysts correlates with implantation and live birth in IVF-FET cycles. Therefore, the selection of euploid blastocysts based on the presence of a higher grade ICM is the most predictive factor that determines success among those undergoing IVF with PGT-A.