Preimplantation genetic screening on patients with meiotic disorders

Abstract

OBJECTIVE: Meiotic disorders increase the percentage of sperm carrying chromosome abnormalities that can rise the rate of abnormal embryos. The major difficulty in diagnosing meiotic disorders is that they can only be directly diagnosed trough the study of meiosis in testicular biopsies. The two aims of this study have been: 1)To compare the aneuploidy rate in embryos of males with meiotic disturbances with a control group; 2) To analyze the outcomes obtained after the Preimplantation Genetic Screening (PGS) cycles. DESIGN: Prospective cohort study. MATERIALS AND METHODS: The study included 32 patients whose evaluation of meiotic stages, chiasmata count and meiotic characterization resulted abnormal. The analysis was performed in classic meiotic preparations of processed unilateral testicular biopsy. A single blastomere from 185 embryos coming from 42 treatment cycles was evaluated, being abnormal meiosis the only indication for PGS. Biopsy was performed on day 3 embryos and FISH was assessed for chromosomes 13,15,16,18,21,22, X and Y. A control group of 31 fertile couples performing 33 cycles with 200 embryos evaluated was used for statistical comparisons. This group underwent PGS for sex-linked diseases. Fisher's exact tests with Yates correction were used for statistical analysis. RESULTS: When male had abnormal meiosis there was a higher percentage of aneuploid embryos than the control group (57.46 vs 34.0%, p<0.01) gonosome abnormalities (15.47% vs 7.53% p=0.02) and trisomies 13 (4.32% vs 0.05%, p=0.03). However trisomies 21, trisomies 18, haploidy, triploidy and tetraploidy rates were similar. Regarding PGS cycles, both groups obtained comparable clinical pregrancy rate, implantation rate and miscarriage rate (47.06% vs 40.00%; 42.62% vs 34.40%; 12.5% vs 16.7%) being women's mean age and number of embryos replaced similar. CONCLUSION: Meiotic abnormalities have a direct effect on the chromosomal constitution of embryos. PGS should be offered to these patients, because it provides high pregnancy and implantation rate.