Before embryos are implanted, two types of genetic tests can be performed: preimplantation genetic testing for aneuploidy (PGT-A, formerly known as PGS) and preimplantation genetic testing for a monogenic disorder. Using cutting-edge technology, genetic screening during IVF enables you to identify whether embryos have a healthy genetic makeup before transferring them into the uterus. By doing this, genetic defects are kept from being inherited by the babies. Let’s study the two genetic tests in details:
PGT-A
PGT-A is a screening test for the embryo’s chromosomes, which contain all of the genetic material.
The right number of chromosomes in an embryo is 46, with half coming from the egg and the other from the sperm. PGT-A detects the presence of any missing or excess chromosomal material within the test’s resolution. Chromosome abnormalities in an embryo can cause it to fail to implant, miscarry, or have an impact on the health of the newborn child. PGT-A does not modify or correct the embryo’s chromosomes. However, if an embryo passes the PGT-A screening, the dangers outlined above are lower than those of an unscreened embryo.
The key factor determining the chance of faulty chromosomes in an embryo or pregnancy is the age of the egg provider. Because chromosomal results fluctuate between embryos and cycles, there are no perfect estimations of cycle outcomes. PGT-A can be conducted in conjunction with a regular IVF cycle for any individual or couple, however it is most commonly used when the female spouse is above the age of 35.
Another advantage of PGT-A is that it increases our capacity to select the healthier embryos in a cohort, resulting in a higher success rate with a single embryo transfer, when a normal embryo is discovered with PGT-A, lowering the chances of twin pregnancy. PGT-A is a screening test, hence there is a chance of misdiagnosing the embryo’s chromosomes.
PGT-M
Preimplantation genetic diagnosis, also known as preimplantation genetic testing for monogenic (single gene) disorders (PGT-M), is a test offered when someone in the household or family has a known genetic problem. This test, when combined with IVF, can assist in lowering the risk of passing down an inherited disorder. It may be appropriate when both reproductive partners are found to have the same genetic condition (such as cystic fibrosis or sickle cell anemia) when one partner or a close relative has a personal history of a genetic condition, when a female patient is a carrier for an X-linked condition, or when the patient or partner has a balanced chromosome rearrangement (PGT). Families can also utilize PGD when a member of the family needs a bone marrow donor in order to have a child capable of providing matching stem cells.
PGT-M is accessible for many inherited disorders for which the exact mutation has been identified. Because each case is unique, PGT-M requires a referral to a genetic laboratory, which must subsequently create a specific test. This process normally takes around three months before an IVF round may begin.
PGT-M may significantly decrease the risk of having a baby with the condition. It is usually done for couples who do not have trouble conceiving. Many couples are aware that they are at risk because they have a family member who has the disease, but some individuals or couples may be silent carriers. Preconception carrier screening can assist in identifying individuals and couples who are at a higher risk of having a child with a genetic disorder, and PGT-M may become a possibility for them when they are under a good fertility clinic’s care.
There are several types of preimplantation genetic testing (PGT). Your doctor can help you decide what type of testing is acceptable or recommended for you.
How to Prepare for a PGT Appointment?
Before you prepare for PGT, send any previous genetic testing results to your pre-cycle coordinator, prior to the consultation.
Collect health-related information from relatives. The genetic counselor will inquire about three generations of your family (children, siblings, parents, aunts and uncles, first cousins, and grandparents), including:
- Approximate relative ages or the age and cause of death.
- Known health issues, including approximate age at diagnosis and precise type if known (for example, type of cancer and age at diagnosis).
- If applicable, check to see if your spouse is available for the appointment.
- When possible, all partners should be present to collect and examine family history, as well as discuss genetic testing alternatives and results.
- If you believe you can continue with PGT in a cycle, both you and your partner must sign consent paperwork.
How is PGT Performed?
PGT is needed in IVF, in which numerous eggs are produced and then harvested directly from the ovaries. These eggs are fertilized with sperm at an embryology lab, and the resulting embryos are grown there for about a week. At this time, the embryo is biopsied, with around 5-10 cells removed. The embryo is then frozen, with the extracted cells sent for genetic examination.
Progenesis’ embryology laboratory staff has substantial experience with embryo micromanipulation and biopsies. Our genetic counselors work closely with the IVF team and the embryology laboratory to ensure that your cycle runs smoothly.
What is the Cost of PGT Testing?
The actual cost of PGT varies depending on the type of testing performed and the amount of embryo samples analyzed, as well as other factors such as potential insurance coverage and the laboratory where the testing will be conducted. Your genetic counselor can offer you cost estimates or connect you with the PGT laboratory’s billing department if needed.
Please keep in mind that the cost of PGT is separate from any other procedure fees, which may include charges for techniques such as embryo biopsy and freezing. Please contact your financial counselor if you have any questions or concerns regarding the estimated costs before the cycle begins.