Dr. Konstantinos Pantos Gynecologist, Director of Infertility Dept., GAIA.
IVF with vehicle the preimplantation genetic diagnosis attempts to “open up” to fertile couples. Several candidates are now parents for whose IVF and preimplantation genetic testing is a choice in order to ensure that the baby will be born healthy.
What is PGD?
In couples at risk of having a child with a serious genetic disease, preimplantation genetic diagnosis eliminates the possibility for the woman to gestate an affected fetus and need to terminate her pregnancy.
Preimplantation diagnosis is the set of techniques applied (ie embryo biopsy and molecular analysis) in order to check the embryos for genetic disorders before their transfer to the uterus. After genetic testing is complete, only normal embryos are transferred into the uterus so that pregnancy can begin safely.
Is it necessary to perform IVF in order to apply pre-implantation genetic diagnosis?
To apply the preimplantation genetic diagnosis it is essential to create fertilized eggs in the laboratory, a process that is achieved with IVF.
Thus, during IVF, biopsy of fertilized eggs and through diagnosis are carried out in the time interval between egg collection and embryo transfer. Genetic analysis is performed on cells obtained through biopsy and based on the results, the embryos which are "healthy", regarding the disease we are looking for, or the diseased ones, are separated. Healthy embryos are then selected for transfer to the uterus.
What is embryo biopsy and when done?
For preimplantation testing be carried out, prior sapling of cells (biopsy) from the embryos is necessary. The biopsy may be done at different stages of embryo development in the laboratory.
The first clinical applications in preimplantation genetic diagnosis, made at the Hammersmith hospital in London, about 15 years ago, emerged from biopsy at the groove stage, i.e. removing one or two cells of the embryo, on the third day after fertilization, and since then it is the most popular method in all centers in the world.
At our center, the method of blastocyst biopsy i.e. removing 5-10 cells from the outer shell of the blastocyst on the 5th day of life of the embryo (blastocyst is the embryo at its 5th day of development after fertilization and consists of 100 -150 cells), comprises a pioneer application since 2004.
What are the indications for preimplantation genetic diagnosis, i.e. what diseases is it applied for?
Practically, one can say that preimplantation diagnosis can be carried out for all genetic diseases, since we know the genetic disorder.
Apart from diagnosis of genetic diseases, has it been applied in other cases?
For example, some years ago it was announced by our center that the first child came to life (was born) in Greece in order to save his sister who suffers from thalassemia.
This couple (both carriers of β thalassemia mutations), had a request to primarily acquire a second healthy child to complete their family while helping their first child who is sick. A mild ovarian stimulation protocol was followed for the woman and then the methods of IVF and biopsy of the fertilized ova. In cell sample from each fertilized egg a screening of mutations for thalassemia was performed and concurrently histocompatibility testing with the existing child in the family. Only one single fertilized egg healthy and histocompatible with the sister was found, which was transferred to the uterus of the woman and a healthy child was born. During childbirth blood was collected from the umbilical cord, from which stem cells were isolated and frozen in order to be transplanted in the future for treatment of the first child.
Through the transplantation of stem cells and hematopoietic tissue, the older child was successfully treated from thalassemia. Already, with the analogous process in two families with sick children with chronic granulomatous disease, where the methodology of preimplantation genetic diagnosis and histocompatibility was applied, the children were successfully treated after transplantation of similar sort. Note that these children usually have a life expectancy until puberty and die as a result of common infections as well as virus infections.
Simultaneously, in Britain the first child, who was tested before implanted in the uterus for whether carrying the genes responsible for breast cancer, was born.
What process was used? Is it applied in our country?
Preimplantation genetic diagnosis is widely applied to exclude genes, which are certain to cause a hereditary disease such as thalassemia. In Britain preimplantation diagnosis was applied to exclude genes, which influence the quality of life expectancy or survival. Genes, i.e., related to cancer, in the particular case of breast cancer, or in other cases, of ovarian or colorectal cancer, or combinations of genes associated with other diseases such as diabetes.
World's first and major achievements of Dr. Pantos’ scientific teem
- The scientific work is included in the global history of IVF (www.IVF-Worldwide.com), i.e. the history of IVF
- In 2007, ATHENS’ GENESIS attracted the attention of the international news network CNN for the delivery of a healthy child from a LEBER syndrome carrier family bodies that until then had delivered two blind children. The news went around the world through the screens for several days
From Dr. Pantos’ scientific team:
- the first child in the world was born after blastocyst biopsy free of thalassemia in 2004
- the first child in the world was born, free of chronic granulomatous disease, which saved its little sister, giving stem cells for transplantation in 2005
- the first births in the world of healthy children were carried out, which according to their genes, and without our intervention it was likely to suffer from rare genetic diseases such as Cadasil’s disease (2006), congenital adrenal hyperplasia (2006), the maxillofacial dysostosis syndrome FSHD (2007)
- the first pregnancy in Greece was achieved after preimplantation genetic diagnosis of all chromosomes with the Array-CGH method in 2010.