Reliability of short comparative genomic hybridization in fibroblasts and blastomeres for a comprehensive aneuploidy screening: First clinical application

Background: Comparative genomic hybridization (CGH) is a valuable alternative to fluorescence in situ hybridization (FISH) for preimplantation genetic screening (PGS) because it allows full karyotype analysis. However, this approach requires the cryopreservation of biopsied embryos until Results: are available. The aim of this study is to reduce the hybridization period of CGH, in order to make this short-CGH technique suitable for PGS of Day-3 embryos, avoiding the cryopreservation step. Methods: Thirty-two fibroblasts from six aneuploid cell lines (Coriell) and 48 blastomeres from 10 Day-4 embryos, discarded after PGS by FISH with 9 probes (9-chr-FISH), were analysed by short-CGH. A reanalysis by the standard 72 h-CGH and FISH using telomeric probes was performed when no concordant Results: between short-CGH and FISH diagnosis were observed. The short-CGH was subsequently applied in a clinical case of advanced maternal age. Results: In 100 of the fibroblasts analysed, the characteristic aneuploidies of each cell line were detected by short-CGH. The Results: of the 48 blastomeres screened by short-CGH were supported by both 72 h-CGH Results: and FISH reanalysis. The chromosomes most frequently involved in aneuploidy were 22 and 16, but aneuploidies for the other chromosomes, excepting 1, 10 and 13, were also detected. Forty-one of the 94 aneuploid events observed (43.6) corresponded to chromosomes which are not analysed by 9-chr-FISH. Conclusion: SWe have performed a preliminary validation of the short-CGH technique, including one clinical case, suggesting this approach may be applied to Day-3 aneuploidy analysis, thereby avoiding embryo cryopreservation and perhaps helping to improve implantation rate after PGS. © 2010 The Author.