There are two PGD tests for chromosomal disorders and single gene disorders. In this section, we will discuss the PGD procedure for chromosomal disorders.
What is PGD for Chromosomal Disorders?
PGD (Preimplantation Genetic Diagnosis) is the genetic testing of cultured embryos before transfer to the mother’s uterus.
Why is the PGD test performed?
Human embryos have 46 (23 pairs) chromosomes, half of which are from the mother and half from the father. The risk of numerical or structural abnormalities in embryos may be increased due to several factors, such as the age of the prospective mother, structural chromosomal disorders (translocation, etc.) in the mother or the father (or both), and different biological/environmental causes. Most chromosomal disorders are “incompatible with life”, i.e. they stop the development of the embryo or prevent its implantation to the uterus, while part of the embryos that succeed to implant to the uterus (trisomy 13, 16,18,21,22; monosomy X) end up in miscarriages. A few (microdeletion syndromes, monosomy X [turner syndrome] and trisomy 21 [down syndrome]) end in live births but cause disorders with intellectual disability. Thanks to the PGD test, the identification and transfer of normal embryos in the aforementioned risk groups reduces the risk of miscarriages and increases the success of the IVF treatment.
Who is the PGD test performed on?
It is recommended that this test, which is used more frequently among IVF patients in the world and in our country, be performed on couples with a high risk of developing embryos with chromosomal abnormalities.
The PGD approach for chromosomal disorders is recommended in the following situations among others:
• Advanced maternal age
• Recurrent miscarriages,
• Recurrent IVF failures,
• Carrier(s) of translocation or inversion
• Severe male infertility,
• Couples with a history of pregnancies with chromosomal abnormalities.
How is the PGD test performed?
The PGD test is performed on the cell(s) collected via biopsy on the 3rd or 5th day of embryonic development. Nowadays, with the development of the freezing techniques and culture methods, the PGD test is mostly performed upon embryos in the blastocyst stage (5th day or 6th day). The embryo on which the test is performed is frozen using the vitrification technique; and passes onto the next stage of the treatment according to the results. The embryo freezing does not prevent embryo development, nor does it decrease the chance of pregnancy when appropriate conditions are met and the procedure is performed by an experienced embryologist. On the contrary, many scientific studies show that, when compared to fresh embryo transfer, the chances of success increase after a freeze-all stage.
What methods are used in the PGD test?
The NGS (Next Generation Sequencing) technique is used in our centres. With this technique, all available chromosomes, mosaicism and chromosome fragments can be safely examined in a short time.
How much does the PGD test cost?
Due to current legistation, we cannot publish our PGD test price on our website. For more information on the process and a quote, please fill in our contact form or call us on +90 444 3 949.
