GENOTYPING OF EMBRYOS USING FRAGMENTAL STR ANALYSIS AFTER WHOLE GENOME AMPLIFICATION

Aim. To develop a method for determining the maternal or paternal origin of chromosomal aneuploidies in embryos by performing STR analysis for patients who undergo assisted reproductive technologies (ART) programs. Materials and methods. The development of the method was carried out using biopsy material of the trophectoderm in embryos of 58 couples of patients (116 persons). Preimplantation genetic testing for aneuploidy (PGT-A) was performed using high-throughput sequencing. Determination of the origin of aneuploidy was performed by fragment analysis of STR markers. Results. After After PGT-A, aneuploidy was detected in 67 embryos (41%); euploid embryos were 65 (40%); mosaic forms were found in 28 (17%) embryos. Primers have been developed for the analysis of chromosomes 1, 3, 4. Development of primers for analysis of 1, 3, 4, 5, 6, 7, 9, 11, 12, 13, 14, 15, 16, 19, 22 and X chromosomes was performed. The analysis of chromosome 16 (n = 7 embryos), chromosome 19 (n = 5 embryos) and chromosome 22 (n = 8 embryos) showed that this approach can be used to identify both maternal and paternal origin of aneuploidy. Conclusion. A technological possibility of carrying out STR fragment analysis with purpose of genotyping of embryos using various products of whole genome amplification was shown. It makes possible to carry out PGT-A and PGT-M together with embryo genotyping without the need for repeated biopsies. The study parental contribution to the development of embryonic aneuploidy in future will allow to choose the most optimal tactics for managing patients with repeated unsuccessful attempts of ART and past miscarriages.

assisted reproductive technologies, embryo, PGT-A, PGT-M, chromosomal abnormalities, aneuploidy, fragment analysis, genotyping