Sperm and blastomere aneuploidy detection in reproductive genetics and medicine.

Sperm and blastomere aneuploidy detection in reproductive genetics and medicine

Luca Gianaroli, M. Cristina Magli, Anna P. Ferraretti J. Histochem. Cytochem. 2005; 53:261-268

The use of multiple probes in fluorescence in situ hybridization (FISH) technique has permitted the simultaneous analysis of several chromosomes both in blastomeres and spermatozoa. The results obtained by preimplantation genetic diagnosis (PGD) for aneuploidy provide information on the embryonic chromosomal status, enabling the selection of those embryos carrying an euploid condition. This strategy has a direct impact on implantation as documented for patients with a poor prognosis for pregnancy, who have the tendency to generate high proportions of chromosomally abnormal embryos. Besides its clinical relevance, PGD for aneuploidy has contributed information on early phases in human embryology by clarifying the molecular basis in some cases of irregular development. Multicolor FISH has also been applied to study chromosomes on spermatozoa. Experimental strategies and modifications enabled the analysis to be extended to samples with a very low number of sperm cells, including samples retrieved by the genital tract or directly from the testicular tissue. The results obtained confirmed that the incidence of aneuploidy increases proportionally with the severity of the male factor condition. This observation suggests that, in selected cases, the paternal contribution to aneuploidy in the developing conceptus could be more relevant than expected on the basis of general data from abortuses and live births.