Stability of aneuploidy rate in polar bodies in two cohorts from the same patient

Whole-chromosome aneuploidy analysis in human oocytes: focus on comparative genomic hybridization

The study of aneuploidy in human oocytes, discarded from IVF cycles, has provided a better understanding of the incidence of aneuploidy of female origin and the responsible mechanisms. Comparative genomic hybridization (CGH) is an established technique that allows for the detection of aneuploidy in all chromosomes avoiding artifactual chromosome losses. In this review, results obtained using CGH in single cells (1PB and/or MII oocytes) are included. The results of oocyte aneuploidy rates obtained by CGH from discarded oocytes of IVF patients and of oocyte donors are summarized. Moreover, the mechanisms involved in the aneuploid events, e.g. whether alterations occurred due to first meiotic errors or germ-line mitotic errors are also discussed. Finally, the incidence of aneuploid oocyte production due to first meiotic errors and germ-line mitotic errors observed in oocytes coming from IVF patients and IVF oocyte donors was assessed.

Preconceptional diagnosis for Robertsonian translocation as an alternative to preimplantation genetic diagnosis in two situations: a pilot study

INTRODUCTION

Preimplantation genetic diagnosis (PGD) is widely used for women heterozygous for a Robertsonian translocation. Preconceptional diagnosis (PCD), performed before fertilization, may be an alternative to PGD, especially in countries where PGD is restricted or prohibited, as in France. It could also give different information and clarify the influence of reproductive and obstetric history.

METHODS

In our study, translocation was diagnosed before ICSI in five cases (group A), and after newborn or fetal aneuploidy or miscarriage in two cases, (group B).

RESULTS

First polar body (PB1) analysis using acrocentric centromeric probes was done for 85 PB1s, and aneuploidy rate was at 42.4%. Oocyte aneuploidy rate differed (p<0.0001) between groups A and B (30% vs 84%). Despite the small group sizes, we demonstrate a correlation (p=0.0358) of aneuploidy rate in polar bodies after 2 or more attempts. Three live births were recorded, all in group A.

DISCUSSION

PCD could thus be an alternative to PGD. This pilot study also provides new prognostic information taking into account the women's natural history, but further confirmation is required.