Chapter 18: - Preimplantation genetic diagnosis: the future

Summary

Genetic diagnosis of an oocyte or early embryo is still achieved by sampling, or biopsying, cellular material, performing a test on the material, and inferring the genetic constitution of the oocyte or embryo. Embryos also lose cells when they are thawed after cryopreservation and this has been used as a model to determine if cell loss affects embryo development. Comparative genomic hybridization (CGH) is a molecular cytogenetic technique which enables enumeration of all chromosomes in single interphase cells. An alternative to metaphase CGH for aneuploidy detection would be to use a microarray, rather than metaphase chromosomes, as the template for the in situ hybridization. Cryopreservation methods that result in significantly improved cell and embryo survival have been reported for biopsied embryos. An alternative approach to embryo freezing is vitrification, which avoids the damaging effects of ice crystal formation.