Single Cell FISH Analysis In Preimplantation Genetic Diagnosis For Aneuploidy Screening

To investigate whether the results obtained from a 2-cell biopsy of frozen-thawed embryos and fluorescence in situ hybridization (FISH) analysis are representative for the chromosome constitution of the remaining embryo on day 5. Cryopreserved embryos were thawed and from surviving embryos two blastomeres were biopsied. FISH analysis was performed for chromosome 13, 18, 21, X and Y. After biopsy, the embryos were cultured until day 5 and further analysed using the same probe panels. In all, 15 embryos were available with a diagnosis based on two blastomeres on day 3 and confirmatory studies on day 5. In 10 of these 15 cases the initial diagnosis could be confirmed. The embryo development is rarely damaged by a 2-cell biopsy. The confirmation rate of the rusults obtained on day 3 depends on the interpretation and ishigher when considered from a clinical than from a cytogenetic point of view.