Recent studies have shown that the transfer of a mosaic embryos, many of them containing partial aneuploidies, can result in the delivery of a euploid children ...
TABLE 1. Distribution of embryos by age group and diagnosis
Egd
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Normal 44.10% 43.19% 33.84% 27.40% 16.37% 12.17% Embryos Embryos 39.30% 41.07% 55.17% 64.20% 76.87% 84.66% with other Abnormalities Embryos 16.59% 15.74% 10.99% 8.40% 6.76% 3.17% with Partial Aneuploidies only
Figure 2. Percentage of aneuploidy chromosomes in complex abnormal embryos by age group.
Figure 1. Percentages of embryos with partial aneuploidies, other abnormalities and euploid embryos by age groups.
Figure 3. Highlight of Complex Abnormal embryos carrying at leas one mosaic chromosome by age.
P-23 NEXT GENERATION SEQUENCING (NGS) AND THE RATE OF PARTIAL ANEUPLOIDY IN PREIMPLANTATION GENETIC SCREENING (PGS). Tomas Escudero, Lia Ribustello, Marina Sumarroca, Santiago Munne. Reprogenetics A Cooper Surgical Company, Livingston, NJ, USA. BACKGROUND: The implementation of high resolution NGS for PGS has provided more information for each diagnosis because in addition of providing the same resolution as aCGH with higher accuracy in regards to the copy number of chromosomes and also partial chromosome, with potentially more resolution than array comparative genomic hybridization. Partial aneuploidy could scape undetectable to other PGS techniques like FISH, qPCR and SNP arrays, and targeted NGS, which target discrete loci of the chromosome instead of the genome as a whole. Partial aneuploidy could lead to loss of implantation, pregnancy loss, dimorphism, mental retardation, microdeletion syndromes (retinoblastoma, VCR,.), and maybe predisposition to some cancers. Recent studies have shown that the transfer of a mosaic embryos, many of them containing partial aneuploidies, can result in the delivery of a euploid children, however they have a >50% chance of spontaneous abortion and a 50% decrease in implantation rates. OBJECTIVE: This study aims to determine the true proportion of partial aneuploid embryos and its behavior according to maternal age. MATERIALS AND METHODS: This is a retrospective study of 2184 blastocyst-stage embryos analyzed by NGS resulting from 454 cycles from 15 US fertility centers.
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PCRS Abstracts
Figure 2. Embryos with partial aneuploidies by age (in blue).
Embryos were classified in three categories: Normal embryos, Embryos with Partial Aneuploidies only, and Embryos with other Abnormalities (which may carry additional partial aneuploidies or not). Mosaicism wasn’t considered a factor for this study. RESULTS: Results are summarized in Table 1 and Figure 1. Partial aneuploidy decrease steadily with age, probably due to the displacement of other abnormalities linked with age, whole chromosome aneuploidy and complex abnormals (Fig 2). Euploid embryos decreases with age and embryos with other abnormalities increased with it. The average rate of embryos carrying partial abnormalities is 10.4%. CONCLUSIONS: Our findings showed that partial aneuploidy decreases with age. The mechanism leading to partial aneuploidy are more complicated than the ones producing aneuploidy and mosaicism, as several factors could cause it (paternal age, failures in DNA reparation, embryo culture conditions, radiation, mutagens,.). Also a multiple number of partial aneuploidies in a single embryo may have other causes, for example, one of the members of the couple may carry a karyotypical abnormality, whether in full or with some level of mosaicism in the germ line.
Vol. 105, No. 2, Supplement, February 2016
The average rate of embryos carrying partial abnormalities is just over a 10%, which is a noticeable risk and could lead to failure of implantation rate, increase of pregnancy loss, or even an affected child. SUPPORT: N/A. P-24 FACTORS ASSOCIATED WITH USE OF ELECTIVE SINGLE EMBRYO TRANSFER AND MULTIPLE PREGNANCY RISK AT FERTILITY CENTERS IN THE UNITED STATES. T. Evans,a C. E. Bedient,a,b S. T. Daneshmand,a,b F. C. Garner,a,b B. S. Shapiro.a,b a University of Nevada School of Medicine, Las Vegas, NV, USA; bFertility Center of Las Vegas, Las Vegas, NV, USA. BACKGROUND: The transfer of multiple embryos in cycles of in vitro fertilization is associated with multiple pregnancy and numerous increased maternal and fetal risks. The primary means for controlling these risks is to transfer a single embryo. There has been gradually increasing use of elective single embryo transfer (eSET) among fertility centers in the United States. In 2013, the Centers for Disease Control and Prevention (CDC) reported that 21.4% of fresh embryo transfers in patients
