F. Pellestor

Predictive value of sperm-FISH analysis on the outcome of preimplantation genetic diagnosis (PGD) for a pericentric inversion inv5(p15.3q11.2) carrier

BACKGROUND Pericentric inversions (PIs) are structural chromosomal abnormalities, potentially associated with infertility or multiple miscarriages. More rarely, at meiosis, odd numbers of genetic recombinations within the inversion loop produce recombinant gametes which may lead to aneusomy of recombination in the offspring. METHODS We report a FISH segregation analysis of an inv5(p15.3q11.2) carrier, both in sperm and blastomeres. In sperm, we directly evaluated the proportion of recombinant gametes and compared the results with chromosomal abnormalities found in blastomeres collected from embryos obtained following a preimplantation genetic diagnosis (PGD) procedure. RESULTS A total of 7006 sperm nuclei were analyzed. The size of the inverted segment represented 27% of the total length of chromosome 5. The frequencies of balanced chromosomes (normal or inverted), recombinant chromosomes and unbalanced combinations were 97.1, 0.17 and 2.73%, respectively. Of six embryos, PGD FISH analysis revealed that one was a balanced embryo, whereas five were unbalanced and there were no recombinants. CONCLUSIONS This study demonstrated the value of sperm-FISH analysis in providing reproductive genetic counseling for PI carriers. Our study also highlights the clinical relevance of performing PGD instead of prenatal diagnosis.

Les marqueurs apoptotiques ont-ils leur place comme marqueurs potentiels de l'exploration de l'infertilité masculine ?

Apoptosis is a cell death program involved in different steps of spermatogenesis, first at puberty, at the beginning of spermatogenesis, then in adult testicles by controlling normal spermatogenesis. As a result, apoptosis deregulation can affect spermatogenesis. Many studies have provided evidence that apoptosis deregulation in germinal cells resulted in male infertility. In addition, apoptosis detection in ejaculated spermatozoa arouses a growing interest in research as a reliable marker of spermatozoon quality. The aim of this review is to summarize our knowledge on physiological apoptosis during spermatogenesis, and then analyse the possibility of using apoptotic markers as selective markers of spermatozoon quality to optimize the rate of success of in vitro fertilization.

L’ovocyte et l’embryon : de la morphologie aux gènes

Les taux d’embryons et de grossesses obtenus a partir d’ovocytes fertilises in vitro restent faibles, que ce soit dans le cas de la fecondation in vitro classique (FIVc) ou dans celui de la micro-injection intracytoplasmique de spermatozoides (ICSI). Ces echecs de la fecondation in vitro sont le plus souvent associes a une mauvaise qualite embryonnaire, dependant elle-meme de la qualite des gametes. Jusqu’a present, les gametes et les embryons sont selectionnes sur des criteres exclusivement morphologiques, et par consequent subjectifs. La connaissance de l’expression des genes dans les ovocytes, les cellules du cumulus, et de l’embryon precoce, par la technique de microarray, devrait permettre de mieux apprehender et comprendre le developpement ovocytaire et embryonnaire precoce. A plus long terme, ce type d’approche favorisera l’identification de marqueurs fiables de la qualite ovocytaire et embryonnaire. L’utilisation d’une signature genetique de la qualite ovocytaire et embryonnaire devrait, quant a elle, permettre d’ameliorer les taux de reussite de FIVc et d’ISCI bases essentiellement a l’heure actuelle sur des criteres morphologiques.