A Short Comparative Genomic Hybridisation (CGH) method has been developed to carry out preimplantation genetic screening (PGS) by analysing all chromosomes and transferring selected embryos to the recipient uterus in the same in vitro fertilisation cycle. This eliminates the need to freeze them.
The technique has been applied to the screening of chromosomal anomalies in cases of advanced maternal age, recurrent miscarriages or repeated implantation failures.
Short-CGH achieved, as part of a PGS programme, the pregnancy of a woman whose partner is carrier of two chromosomal translocations, a very rare case which commonly causes infertility, miscarriages or physical and/or mental malformations in the newborn.
The technique developed is the result of a doctoral thesis by Mariona Rius, member of the research team belonging to the Cell Biology and Medical Genetics Unit of the Department of Cell Biology, Physiology and Immunology at Universitat Autnoma de Barcelona (UAB). The project received funding from the Spanish Health Research Fund and was carried out under the Eugin Research Chair - UAB.
Preimplantation Genetic Screening (PGS), through in vitro fertilisation (IVF) treatment, allows selecting healthy embryos with no anomalies which are later transferred to the recipient uterus, thus increasing chances of implantation.
Presently, the methodology most frequently used is the analysis of one cell of the embryo the third day of its development through fluorescent in situ hybridisation (FISH), which routinely analyses only nine of the 24 different types of existing chromosomes. The selected embryos are transferred to the recipient uterus four days after beginning, in the same IVF cycle. The implantation rate using this technique is 14%.
An alternative technique, used in few centres in the world, is Comparative Genomic Hybridisation (CGH) which allows for a comprehensive cytogenetic analysis of all chromosome
|Contact: Maria Jesus Delgado|
Universitat Autonoma de Barcelona