In her doctoral thesis, Mariona Rius developed a short-CGH method which allows the full karyotype study of the cell (blastomere) with a very reduced hybridisation period (from 72 to 12 hours). Using only one procedure and with the same efficacy, short-CGH permits scientists to detect not only aberrations in the number of chromosomes (numerical), but also alterations in chromosome fragments (structural). Thus the embryos selected chromosomally normal can be transferred within the same IVF cycle.
The technique was applied clinically in the screening of chromosomal abnormalities in cases of advanced maternal age, recurrent miscarriages or repeated implantation failures. The implantation rate of transferred embryos reached 60%. It was also used, for the first time in a PGS programme, to obtain a successful pregnancy of a woman whose partner is carrier of two chromosomal translocations, one reciprocal and the other Robertsonian. This is a very rare case which frequently causes infertility, miscarriages or physical and/or mental malformations in the newborn. Of the 16 embryos analysed in three consecutive IVF cycles, the only embryo without chromosomal imbalances was transferred to the woman, who is currently in the third trimester of her pregnancy.
Given the results obtained in this first research phase, researchers are confident that the short-CGH method will be applied in more PGS tests.
|Contact: Maria Jesus Delgado|
Universitat Autonoma de Barcelona