Preimplantation Genetic Diagnosis PGT-M

Preimplantation Genetic Diagnosis (PGD-M) is based on the principle of revealing the structural and numerical disorders of the chromosomes or recognizing the diseases known to exist and inherited through a single gene before the embryo is transferred to the uterus.

For this purpose, cell samples are taken from the embryos obtained after the in vitro fertilization treatment applied to the couple and the embryos are frozen and stored. After the examinations required by the existing medical condition (an anomaly in chromosomes, a detected genetic disease, etc.) in the cell samples taken are performed, the embryo, which is reported as healthy, is transferred into the uterus. We recommend that all chromosomes be screened, in addition to embryos, with Preimplantation Genetic Screening (PGT-A) in couples where we do this.

In couples who will undergo PGT-M for the diagnosis of genetic disease, as a first step, the region of the change in the gene that is known in the family and causing the genetic disease is determined, and then the process of in vitro fertilization and biopsy of the embryo begins.

The number of single gene diseases that can be diagnosed with PGD is increasing day by day. Diagnosis of many single gene diseases such as thalassemia (Mediterranean anemia), spinal muscular atrophy (SMA), various muscle diseases, cystic fibrosis, sickle cell anemia, Tay Sachs disease, Fragile X syndrome and many others, in addition to thalassemia, which is one of the most common blood diseases that concern our country, and embryo level, it is possible with PGT-M. With PGD, it is also possible for couples with a diseased child to have a tissue-compatible sibling for transplantation with stem cells taken from bone marrow or cord blood for this child. In this way, the couple can have both a healthy child and a stem cell or bone marrow transplant for their diseased children.

PGT-M process can be applied in 3 different ways;

• Polar body analysis from egg cell,
• 2. In the cleavage stage Analysis made by taking a cell from the 3rd day embryo,
• 3. Fifth or 6. Analysis of 3-5 cells taken from the trophectoderm part of the embryo that has reached the third day (blastocyst) that will form the baby’s mate. It is recommended to take a cell sample at the blastocyst stage and examine it.
• It is known from studies with a large number of patients made today that 3rd day for PGD. Evaluation made by taking a single cell from a day embryo can have a damaging effect on the embryo and have a negative effect on pregnancy rates.
• 5. or PGT performed with cells taken from the trophectoderm tissue of the embryo, which has reached the 6th day, is considered more advantageous because it allows working with a larger number of cells (3-5 cells). Also 3. It is thought that the harmful effects on the embryo are less as in the day embryo biopsy. Since it provides the opportunity to take more cells instead of a single cell, it is possible to work on more materials and the risk of not being diagnosed is eliminated. However, of course, the laboratory conditions, the presence of competent personnel in the field of embryo biopsy and embryo freezing-thawing are critical for the application of this method. We are also in our clinic 5./6. We prefer to take a biopsy from the embryo and perform PGD.

With the rapid advances in genetic engineering, repair of faulty genes will be possible in the not too distant future. Although the determination of the entire genetic structure at the embryo level and the replacement of diseased genes may seem like fiction today, it seems likely that these will happen in the future. Of course, these practices also have an ethical dimension that cannot be ignored. Therefore, it is very important to carefully examine the ethical dimensions.

Contact information :

Author : Prof. Dr. Mehtap Polat
Telephone : +90 530 011 41 33
E-mail : [email protected]