PGT-M. Why is this method so important for the health of your yet unborn babies?

Articles, News 26. March, 2018

You feel good, you look good, you do not suffer from any serious disease? Yet you can be a carrier of a genetic disease or developmental defect. The preimplantation genetic testing of monogenic diseases (PGT-M) will tell you about your state of health.

There are more than 5000 rare diseases. Which ones are present the most?

Non-functionality of one of your genes has an origin of some monogenic hereditary disease as a consequence. The most common diseases are cystic fibrosis, spinal muscular atrophy, hereditary deafness, Marfan syndrome, Huntington disease and so on. Also, hereditary predispositions to tumoral diseases, for example BRCA1 and BRCA2. Every woman, man, family has their own specific genetic problem, thus individual approach to every person is needed. Thanks to the state-of-the-art laboratories and the great work of specialists it is possible to rule out virtually every rare hereditary disease or developmental defect every day.

Genetic load in family. What does it mean? Is it possible to defend against it?

Partners, very often, find out about the genetic load in family after conceiving a baby with a serious genetic disease. The following decision, whether to undergo abortion or not brings a big psychological and physical tension to both partners. The abortion can have also bad impact on the ability of getting pregnant again.

Thanks to PGT-M it is possible to prevent conceiving a handicapped child. Thanks to PGT-M it is possible to choose only a healthy embryo for the transfer in the uterus.

What embryo is then the promising and appropriate from the genetic point of view for the transfer in uterus?

The preimplantation genetic testing of monogenic diseases (PGT-M), before called the preimplantation genetic diagnostic (PGD), represents a method that tells us with certainty close to 100 % whether the examined embryo is promising for the transfer in uterus. How does this promising embryo look like? The embryo is healthy, it is not a carrier of a disease and does not have any genetic load connected with the future development of a disease.

What happens before and during PGT-M?

PGT-M is connected only with methods of assisted reproduction and extracorporeal fertilization. After all the necessary examinations and the consultation about the whole process with the clinic geneticist is done, it is possible to proceed to the hormonal stimulation and to the oocytes retrieval. Once the oocytes are fertilized and cultured for 5-6 days and they reach the stage of a blastocyst, the biopsy is performed (a sample of approximately 7 cells is taken) using a micromanipulator. The DNA cells taken by this method serve to establishing the genetic heritage of the embryo. It is a delicate method, it does not represent any risk to the future fetus.

Embryo transfer of a healthy embryo.

After the biopsy, all the embryos are frozen – vitrificated – carefully. This step provides enough time for the genetic examination and, especially, for better preparation of endometrium (uterine mucosa). We observe higher success rate if the transfer is performed in the following menstrual cycle of a woman.

Once all the embryos are examined and evaluated as suitable from the genetic point of view, it is possible to proceed to the embryo transfer of one thawed blastocyst; it is so-called cryo-embryo transfer (KET). If the couple has more promising embryos, they can be used in case the first transfer was not successful or, in the future, if the couple would like to have another baby.

What are other advantages of PGT-M?

The most secure method for the preimplantation genetic testing of monogenic diseases is Karyomapping. This method makes possible to perform also PGT-A, which is preimplantation genetic testing of aneuploid embryos. Thus, for the transfer in the uterus, are chosen only promising embryos with the correct number of chromosomes.

A big advantage for couples with genetic risks is also the possibility of paying the preimplantation genetic testing by health insurance.