O-209 The incidence of different ploidy alterations in abnormally fertilized oocytes (AFO)-derived embryos

Abstract Study question Which is the incidence of de novo ploidy alterations in different abnormally fertilized embryos categories analysed with SNP-array? Summary answer Based on number pronuclei (PN) identified, 0PN were mostly diploid, while 1PN and >2PN-derived showed increased rates abnormalities. What known already Recent development SNP-array haplotyping by sequencing approaches are contributing to expanding preimplantation genetic testing (PGT) clinical utility including level evaluation. When applied euploid derived from AFO, identification abnormal constitution (i.e., haploidy, triploidy, or tetraploidy) could rescue viable diploid otherwise considered non-transferable IVF. However, no definitive evidence has been obtained showing abnormalities each AFO-derived blastocyst category. Here we present 4 years experience application a validated based protocol custom-made algorithm detect defects embryos. design, size, duration Prospective observational study evaluating altered configurations blastocyst. After PN check, AFO samples divided as follow: absence observed (0PN), monopronuclear (1PN), more than two (2.1PN, one smaller additional 3PN). Genetic classification combining PGT-A analysis was performed at Igenomix Italy laboratory between May 2019 January 2023 133 (44 0PN, 59 1PN, 30 >2PN). Participants/materials, setting, methods Multi-centre involving 293 consenting patients advance maternal age (mean=38.6±3.9) undergoing MDA-WGA using Ion ReproSeq kit IonTorrent S5 (ThermoFisher). SNP-array-based test HumanKaryomap-12 NextSeq550 (Illumina). Proprietary genome-wide BAF obtained: expected BAFs 1, 0.5 0 for diploids,1 haploid 0.66, 0.33 triploids, determined frequency allele 300000 SNPs loci. Main results role chance Preclinical validation included 26 status karyotype: 7 triploid re-biopsies, left-overs 12 cell lines. Moreover, inter-platform comparison 72 diploids, 9 8 haploids an alternative targeted-NGS approach, Igenomix, 100% (95% CI= 95.94%-100%) concordance. In this study, total 318 collected indications. Of these, 58.2% (n = 185/318; 95%CI=52.54-63.66) resulted aneuploid. The remaining where subjected assessment. 0PN-derived blastocysts 44/133) 93.2% 41/44; 95%CI=81.34-98.57) cases; only 4.5% 2/44; 95%CI=0.56-15.47) 2.3% 1/44; 95%CI=0.06-12.02) polyploid. 1PN-derived all possible these proportions: 59.3% 35/59; 95%CI=45.74-71.93) haploid, 35.6% 21/59; 95%CI=23.55-49.13) 5.1% 3/59; 95%CI=1.06-14.15) Finally, group 2PN (2.1PN 3PN), 66.7% 20/30; 95%CI=47.19-82.71) polyploid configurations, 33.3% 10/30; 95%CI=17.29-52.81) diploid. No Chi-square significant overall correlation category (p < 0.05). Collectively, evaluation embryos, allowed use euploid/diploid not transfer. Limitations, reasons caution Ploidy assessment tested distinguish triploids tetraploids. Parental origin chromosomal set be without analysing parental DNA. way performing check have affected classification. future studies will focus outcomes following embryo Wider implications findings An predictive correspondent status, doesn’t represent clear indication Nevertheless, proportion can rescued types potentially increasing achieve live birth. Trial registration n/a