Статьи

Objectives

To determine pregnancy rate after comprehensive chromosome screening (CCS) using PGD NGS in frozen embryo transfer cycles after blastocyst’s trophoectoderm biopsy.

Material and methods

40 patients who decided to undergo PGD on 24 chromosomes on blastocystes with vitrification and frozen embryo transfer were included in the study as a investigated group. As a control group we adjusted 74 cases which were comparable in age, anty -mullerian hormone level (AMH), antral follicle count (AFC) and causes of infertility. First IVF cycles were taken under consideration.

Results

On 40 cycles we received on average 6.7 blastocystes per patient. We received 30.4% normal results, which allowed us to transfer 1.4 ± 0.6 vitrified blatocystes in frozen embryo transfer. The pregnancy rate was more than 30% higher when compared to control group with fresh blastocystes without PGD transfers (50.0% vs. 18.9%, p<0.006 respectively). The difference in implantation rate was more than 20% (32.4% vs. 11.5%, p<0.05). The difference in pregnancy loss was more than 8% (11.1% vs. 3%, p<0.52).

Conclusion

NGS PGD technology is very useful and should replace aCGH technology soon. It allows to personalize the method and could be in parallel used for all PGD indications. The performing time is the biggest limitation of NGS.

Relative mitochondrial DNA copy number assessed during next generation sequencing (NGS) for cleavage-stage preimplantation genetic diagnosis (PGD) depends on embryo ploidy status but is independent from patient age, embryo gender, embryo morphology or embryo ability to implant.

Preimplantation Genetic Diagnosis (PGD) used in assisted reproduction techniques is designed to provide help for couples trying to conceive a child, as it helps deliver healthy offspring. After in vitro fertilization, material is collected from the 3-day-old embryo, or increasingly often, from the trophectoderm of a blastocyst. Selection of the diagnostic method depends on the testing center, but methods such as aCGH (Comparative Genomic Hybridization Array) and NGS (Next-Generation Sequencing) are supposed to have the highest reliability and precision. This paper presents a review of the most important methods used in PGD, their advantages and disadvantages as well as efficacy in the procedures in which they are used.

Preimplantation genetic diagnosis (PGD) is well established method for treatment of genetic problems associated with infertility. Moreover, PGD with next-generation sequencing (NGS) provide new possibilities for diagnosis and new parameters for evaluation in, for example, aneuploidy screening. The aim of the study was to report the successful pregnancy outcome following PGD with NGS as the method for 24 chromosome aneuploidy screening in the case of Robertsonian translocation. Day 3 embryos screening for chromosomal aneuploidy was performed in two consecutive in vitro fertilization (IVF) cycles, first with fluorescent in situ hybridization (FISH), and then with NGS-based protocol. In each IVF attempt, three embryos were biopsied. Short duration of procedures enabled fresh embryo transfer without the need for vitrification. First IVF cycle with the embryo selected using PGD analysis with the FISH method ended with pregnancy loss in week 8. The second attempt with NGS-based aneuploidy screening led to exclusion of the following two embryos: one embryo with 22 monosomy and one with multiple aneuploidies. The transfer of the only euploid blastocyst resulted in the successful pregnancy outcome. The identification of the euploid embryo based on the NGS application was the first successful clinical application of NGS-based PGD in the case of the Robertsonian translocation carrier couple.

Most of the current preimplantation genetic screening of aneuploidies tests are based on the low quality and low density comparative genomic hybridization arrays. The results are based on fewer than 2,700 probes. Our main outcome was the association of aneuploidy rates and the women’s age. Between August–December 2013, 198 blastocysts from women (mean age 36.3+-4.6) undergoing in vitro fertilization underwent routine trophectoderm biopsy. NGS was performed on Ion Torrent PGM (Life Technologies). The results were analyzed in five age groups (<31, 31–35, 36–38, 39–40 and >40). 85 blastocysts were normal according to NGS results. The results in the investigated groups were (% of normal blastocyst in each group): <31 (41.9%), 31–35 (47.6%), 36–38 (47.8%), 39–40 (37.7%) and >40 (38.5%). Our study suggests that NGS. PGD is applicable for routine preimplantation genetic testing. It allows also for easy customization of the procedre for each individual patient making personalized diagnostics a reality.