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NGS based translocation testing has been widely used as the possibility of detecting other chromosomal aneuploidies. Some studies claimed that balanced translocation carriers may have an increased risk for aneuploidies unrelated to translocation due to inter-chromosomal effect (ICE). Translocation causes unusual segregation of chromosomes involved in translocation. Furthermore this rearrangement may have an effect on the segregation of other structurally normal chromosomes during meiosis. Here we present a report of aneuploidy and complex aneuploidy rates among the embryos derived from patients carrying balanced chromosomal rearrangements (reciprocal or robertsonian translocations). Whole Genome Amplification (WGA) was performed using SurePlex DNA Amplification System (Illumina, USA) and DOPlify (PerkinElmer Health Sciences - Australia). on biopsied cells. Veriseq PGS kit was used for further processing of WGA samples. BlueFuse Multi Software was used to analyse the data obtained from Miseq System. In this study, we collected 705 embryos from 168 patients with an average age of 31. At least one of the couples was previously reported to be a translocation carrier. According to our findings, 25.6% of these embryos was euploid and 69,4% was aneuploid/complex aneuploid (mosaic embryo results were excluded). 29.33% aneuploidy was detected in translocation of interest only. The rest (39.43%) was due to aneuploidy of other chromosomes. According to our in house PGT-A data (7200 embryos collected from 2177 patients) sum of aneuploidy and complex aneuploidy rates was 45.8. Overall these results fail to provide any support for the presence of an ICE. In balanced chromosomal rearrangement carriers PGD by NGS array not only detects unbalanced chromosomal rearrangements due to chromosomes involved in translocation but also detects the possibility of other chromosomal aneuploidies. According to our findings, aneuploidy and complex aneuploidy rates do not increase in the embryos obtained from PGT-SR group of patients. Moreover, in addition to translocation chromosomes, we observed an additional aneuploidy risk related to other chromosomes in these embryos. Our data supports previous studies suggesting that ICE in embryos derived from balanced chromosomal rearrangement carriers is elusive. On the other hand average maternal age of PGT-A patients is significantly higher than PGT-SR group (35.1 vs 31.2 respectively). Although it is thought that increased maternal age may cause aneuploidy in some of the cases, some embryos have an increased aneuploidy rate regardless of maternal age. Nevertheless euploid embryo ratio in PGT-SR group is compared to PGT-A is relatively lower (25.6 vs 36.7) thus our results emphasize the importance of 24 chromosome scan in embryos derived from balanced translocation carriers [ABSTRACT FROM AUTHOR]

Preimplantation Genetic Testing (PGT) has been performed since 1989 and utilized in the diagnosis of all genetic conditions at preimplantation stage (1). In the previous years, only a disorder could be diagnosed with the use of multiplex nested PCR in PGT applications. Increased use of trophectoderm biopsy and vitrification together with Whole Genome Amplification (WGA) technology enabled the detection of single gene disorders together with 24 chromosome screening. This approach allowed us to select healthy and chromosomally euploid embryos. Even though single gene disorder carrier patients are mostly young and fertile, they still have high risk of spontaneous miscarriage. In the recent years, it has been reported that when the embryos are screened for aneuploidy (PGT-A) in addition to single gene disorder testing (PGT-M), pregnancy rates can be increased from 45% to 68% and spontaneous miscarriage rates decreased from 15% to 5%. 34 single gene disorder patients, whose embryos were found to be healthy in terms of single gene disorder, were included in this study and these embryos were further screened for aneuploidy using Next Generation Sequencing (NGS) technology (2). On the 5th and 6th days of embryonic development, WGA was performed using SurePlex DNA Amplification System (Illumina, USA) and DOPlify (PerkinElmer Health Sciences - Australia). Following multiplex nested PCR on WGA samples, fragment analysis for haplotyping and sequence analysis for mutation detection were performed. Embryos found to be suitable for transfer regarding the single gene disorder have further been screened for aneuploidy using NGS technology with VeriSeq PGS Kit (Illumina, USA). This study was conducted for single gene disoder and 24 chromosome screening in 44 patients with an average age of 34. 280 embryos derived from these patients were included in PGT-M. Among 153 embryos that were found to be suitable for transfer after PGT-M, PGT-A was performed on 121 embryos upon patients' requests and 49% of these embryos were euploid. Embryo transfer could not be performed in 12 patients due to the absence of euploid embryos. According to the data we acquired, 64% pregnancy was achieved in the rest of the patients. While pregnancy ratio can be improved with this approach, Allele drop out (ADO) and contamination errors are still major limitation which can lead to misdiagnosis of embryos. ADO ratio was demonstrated to be 25% in PGT for blastomere cells, whereas this ratio drops down to 5% when 5-7 cells obtained by trophectoderm biopsy are tested. Thus trophectoderm cells are more appropriate for PGT-M applications combined with PGT-A. Since stable and homogenous amplification of the entire genome is a crucial step, optimised WGA technologies will be a key factor in these applications. [ABSTRACT FROM AUTHOR]

Preimplantation Genetic Testing for Aneuploidy (PGT-A) has been an important and promising option for the couples experiencing repeated IVF failures in the recent years. Next Generation Sequencing (NGS) has become a popular technology in the last years for The utilization of PGT-A. In this way, pregnancy rates increased by the selection and transfer of euploid embryos with a higher chance to implant and maintain a healthy pregnancy. Additionally, use of NGS technology is advantageous in the selection of embryos that do not carry any chromosomal abnormalities due to inherited structural rearrangements with high resolution, which is extremely important especially for translocation carrier patients known as Preimplantation Genetic Testing for Chromosome Structural Rearrangements (PGT-SR). In this study, we report NGS based PGT results of 7436 embryos from 2324 patients including translocation carriers. SurePlex DNA Amplification System (Illumina, USA) and DOPlify (PerkinElmer Health Sciences, Australia) were used for Whole Genome Amplification (WGA) on biopsied cells. WGA samples were further processed using Veriseq PGS (Illumina, USA) and PG-Seq kits (PerkinElmer Health Sciences, Australia). Data obtained from Miseq System were analysed using BlueFuse Multi Software (Illumina, USA) and Nexus Software (BioDiscovery, USA). 7436 embryos collected from 2324 patients were processed in this study. Results of 7213 embryos were interpreted after the elimitation of amplification failure group. Among these embryos, 705 were obtained from translocation carrier patients. Our results show that 36.7% of embryos was euploid and this ratio was 25.6% for translocation carrier patients. For PGT-A and PGT-SR patients, aneuploidy rates were 16.3% and 18.2%, respectively. We observed higher complex aneuploidy in translocation patients (51.6%) compared to the rest of the samples (29.5%). In addition to these findings, we also obtained pregnancy rate data from 1245 embryos of 470 patients. Pregnancy rate per embryo transfer was 62% in the group of patients in the range of 35-39 years, which was 53% in the group of patients over 40 years of age. Our data suggest that this technology is valuable for the selection of euploid embryos and improvement of IVF success together with pregnancy rates. Additional information obtained from NGS application prevents the transfer of aneuploid embryos, which is extremely important especially for translocation carrier patients. Moreover, this technology yielded promising results in the group of patients with advanced maternal age. At the point we have arrived through this aneuploidy testing adventure in embryos started in 1993 with FISH that detects only a limited number of chromosomes, detailed information accumulation obtained from 24 chromosome screening will increase the acceptability of this technique in IVF applications every passing day. [ABSTRACT FROM AUTHOR]