Preimplantation genetic diagnosis

PGD allows the identifications of genetic abnormalities of the embryo while it develops in culture. The method detects certain numerical or structural chromosomal abnormalities in the embryo, which are responsible for known congenital or hereditary diseases.

The abnormal embryos are therefore identified and excluded from the embryo transfer. Only healthy embryos are selected for transfer in the uterus. If the gene causing a genetic disease is located on a sex chromosome, then sex selection is required to avoid development of the disease in the embryo.

This is the only case when embryo selection is performed. Cases that require PGD include -thalassaemia, cystic fibrosis, Down syndrome, etc. PGD has an advantage over conventional prenatal diagnosis methods, ie amnioparacentisis and trophoblast biopsy, as it can avoid potential abortion if the diagnosis is positive for a certain abnormality.

It must be clear that PGD searches for specific abnormalities and does not preclude the birth of a child with a different genetic disease.

Also, PGD can help explore the reasons for repeated implantation failure, by identifying aberrations in the genes that signal programmed cell death (apoptosis).