In the field of assisted reproduction, genetic testing can help minimize the risk of passing on genetic diseases to future children. Have you heard of genetic matching and pre-implantation genetic diagnosis (PGT)? Below, we explain how these tests work.
What Genetic Tests Are Available?
There are two primary types of genetic tests conducted in assisted reproduction clinics: genetic compatibility testing (also known as genetic matching) and pre-implantation genetic diagnosis (PGT).
What Is Genetic Matching?
Most people carry a recessive genetic mutation for some hereditary disease. If both partners carry the same mutation, there is a higher risk that their child could inherit the disease or be a carrier. Genetic compatibility testing can detect mutations in genes associated with these hereditary conditions.
When Is Genetic Matching Recommended, and How Is It Performed?
Genetic matching is recommended for egg and sperm donors, and is optional for couples undergoing assisted reproduction treatments. The test only requires a blood sample, and results are typically available within 2-3 weeks.
What Happens if Incompatibility Is Found Between Partners?
If both partners are found to be carriers of a genetic mutation, there are two options. One option is to perform pre-implantation genetic diagnosis (PGT) on the embryos to ensure that they do not carry the disease. The other option is to use a donor.
In cases of egg donation, if a genetic incompatibility is found between the recipient and the donor, a different donor can be selected to ensure compatibility.
Pre-Implantation Genetic Diagnosis (PGT)
PGT is a test that helps identify and prevent the transmission of genetic diseases by studying embryos before they are implanted. This allows the selection of the healthiest embryos for transfer.
PGT includes three types of studies:
PGT-A (Pre-implantation Genetic Test for Aneuploidy): This test analyzes the number of chromosomes in the embryo using advanced techniques like Next Generation Sequencing (NGS).
PGT-SR (Pre-implantation Genetic Test for Structural Rearrangements): This test looks for structural alterations in the chromosomes.
PGT-M (Pre-implantation Genetic Test for Monogenic Disorders): This test identifies single-gene mutations that cannot be detected through standard karyotype studies and requires detailed DNA analysis.
How Are Cells Obtained for PGT Testing?
Embryo biopsy is performed when the embryo reaches the blastocyst stage (day 5-6 of development). A laser creates a small opening in the embryo's outer layer (zona pellucida), and cells from the trophectoderm (the part that will become the placenta) are extracted for genetic analysis. Since the results take a few days, the embryos are frozen (vitrified) after biopsy. Once the genetic results are ready, the normal embryos can be transferred to the uterus in a future cycle.
Were you familiar with these tests? If you have any questions or are considering genetic testing as part of your fertility treatment, feel free to contact Nicosia Fertility!
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