Structure of chromosomal abnormalities in the cycles of IVF-PGS

Introduction: Limited reproductive potential in humans and the progressive decline of the reproductive health of the population have led to the development of assisted reproductive technologies in recent decades. In order to improve pregnancy rates in couples with reproduction problems, preimplantation genetic screening was introduced into clinical practice. Cultivation of human embryos in vitro in in vitro fertilization cycles (IVF), as well as the possibility of obtaining genetic material during preimplantation genetic screening and diagnosis (PGS / PGD), allow us to estimate the frequency and spectrum of chromosomal abnormalities in human blastocysts. Aim: Analysis of the rate and spectrum of aneuploidies in human blastocysts obtained in the IVF-PGD cycles. Material and methods: A retrospective analysis of the molecular karyotypes of 113 blastocysts obtained in the cycles of assisted reproductive technology IVF-PGD from 47 women was carried out. The whole genomic amplification of DNA from trophectoderm cells was performed using the PicoPlex reagent kit (Rubicon Genomics, USA). Analysis of DNA samples obtained after whole genome amplification was carried out by array comparative genomic hybridization (aCGH) using a GenetiSure Pre-Screen microchip, 8×60K (Agilent Technologies, USA). Results: The efficiency of whole genome amplification was 97.3% (110/113). A balanced karyotype was established in 31% (34/110) blastocysts. The rate of a blastocyst with chromosomal imbalance in the group of women under 35 years old was lower (46.9%) compared to the rate of blastocyst with chromosomal imbalance in the group of women over 35 years old (81.0%) (p < 0.001). 74% of the identified chromosomal abnormalities were aneuploidy, 26% - structural chromosomal abberations. The distribution of aneuploidies had the following structure: autosomal trisomies (41%), autosomal monosomies (48%), aneuploidies of sex chromosomes (7%), autosomal tetrasomies (3%), autosomal nullisomies (1%). Aneuploidies of chromosomes 5, 15, 16, 17, 19, 21 and 22 were noted with the greatest frequency. Conclusions: Analysis of chromosomal aberrations in human embryos at the blastocyst stage showed a high frequency of chromosomal imbalance (69%) and a wide range of both numerical and structural abnormalities of chromosomes. PGS with aCGH allows the selection of blastocysts with a balanced karyotype. According to the results of blastocyst transfers in IVF-PGD cycles, clinical pregnancy occurred in 32 % of cases.

анеуплоидия, преимплантационный генетический скрининг, aCGH, ЭКО, aneuploidy, preimplantation genetic screening, aCGH, IVF