Preimplantation Genetic Testing
How is it done?
The PGT study can only be performed on embryos generated by in vitro fertilization. In addition, it is important to have a good number of embryos since, after the study, the abnormal ones will be discarded and only those diagnosed as normal for the reason for the study will be transferred.
To perform the PGT, it is best for the embryos to be cultured until the blastocyst stage, which is reached on day 3-5 after fertilization. This is the moment when the embryo already has an internal cell mass that will give rise to the fetus, and another external layer also called trophectoderm that will give rise to the placenta. This is when the Embryonic Biopsy is performed.
The Embryonic Biopsy is the technique that allows a small hole to be made in the trophectoderm of the embryo to aspirate 4-5 cells with a micropipette. As these cells will give rise to the placenta, if the technique is performed correctly it should not affect the development of the fetus. Once the biopsy has been performed, the embryo is vitrified or transferred after knowing the results of the study.
PGT-A
It is a tool to detect the existence of an abnormal number of chromosomes expected in an embryo (aneuploidies) that generally cause recurrent miscarriages or failures in embryo implantation.
Indications for performing PGT-A:
Advanced maternal age.
Previous failures in Assisted Reproduction techniques (implantation failure).
Repeated miscarriages.
Severe male factor.
Previous pregnancy with chromosomal abnormality.
Benefits of PGT-A:
Higher pregnancy rates per transfer.
Reduction in miscarriage rates.
Greater chance of having a healthy baby.
It allows the transfer of a single embryo, avoiding the complications associated with a multiple birth.
PGT-M
PGT-M (formerly PGD) is an early genetic diagnosis performed on the embryo before its transfer to the uterus, as part of an IVF treatment.
By genetically analyzing embryos, it is possible to select those that do not have the disease to be transferred to the uterus.
Indications for performing PGT-M:
This test is indicated for couples with a family history or who are carriers of monogenic diseases such as cystic fibrosis, fragile X syndrome or Huntington’s syndrome, muscular atrophy/dystrophies, among others.
These mutations are generally transmitted in families from generation to generation, but it is also possible that they appear for the first time in offspring (de novo).
Benefits of PGT-M:
Prevents the transmission of monogenic diseases to offspring.
Identifies embryos affected by a genetic disease before implantation
Genetic compatibility (genetic matching)
Genetic matching or genetic compatibility testing
This is a study that performs genetic compatibility analysis, detecting thousands of mutations related to more than 300 serious genetic diseases. Thanks to this test, future parents can find out if they are carriers of any of these diseases and avoid transmitting a disease to future children.
The test is performed before starting assisted reproduction treatment, detects more than 300 hereditary genetic diseases and identifies up to 2,600 genetic mutations. Only a blood or saliva test is needed.
This analysis allows the identification of genetic diseases with a poor prognosis in children, such as cystic fibrosis, fragile X syndrome or spinal muscular atrophy, among others.
