The Basics of PGT-M

At Boston IVF, preimplantation genetic testing for monogenic diseases (PGT-M) offers families a way to prevent passing specific genetic conditions to their children. Dr. Pietro Bortoletto, reproductive endocrinologist at Boston IVF, explains how this technology helps reduce the risk of inherited diseases like cystic fibrosis, Tay-Sachs, and many others. Here’s a simplified guide to PGT-M, helping you understand its benefits and how it works.

What is PGT-M?
PGT-M is a form of genetic testing used during the in vitro fertilization (IVF) process to screen embryos for specific genetic conditions caused by mutations in a single gene. These diseases, known as monogenic diseases, are often inherited when both parents carry the same gene mutation. With PGT-M, couples who know they are carriers of conditions such as cystic fibrosis, sickle cell anemia, or Tay-Sachs disease can undergo IVF, have their embryos tested, and only transfer those free of the disease.

The IVF Process and PGT-M
Here’s how the process works:

1. IVF Cycle: An individual with ovaries undergoes an IVF cycle, during which medications stimulate the ovaries to produce multiple eggs. These eggs are retrieved and fertilized with sperm in the lab to create embryos.
2. Embryo Development: Over 5-7 days, the embryos grow and develop into the blastocyst stage, where they are ready for testing.
3. Embryo Biopsy: At this stage, a small number of cells (usually 2-10) are taken from the embryo’s outer layer (the trophectoderm), which will later form the placenta. These cells are then sent to a genetic testing lab.
4. Genetic Testing: The lab tests the cells for the specific genetic condition, such as cystic fibrosis or Tay-Sachs, and identifies embryos that are free of the condition.
5. Embryo Transfer: Only embryos that are free from the disease are selected for transfer back into the uterus, significantly reducing the risk of having a child with the inherited condition.

Why PGT-M?
PGT-M is particularly beneficial for couples who are known carriers of genetic conditions. It allows them to:

• Prevent the inheritance of genetic diseases like cystic fibrosis, Huntington’s disease, or sickle cell anemia.
• Plan for the future by selecting embryos that are free from the specific genetic mutation, improving the chances of successfully having a child.

Success and Considerations
While PGT-M is an incredibly powerful tool, it is not without limitations. For example:

• Success Rates: The success of PGT-M depends on the number of embryos available for testing and the age of the egg-producing individual. Younger people tend to have more viable embryos, increasing the chances of finding healthy ones.
• False Positives/Negatives: Though rare, there is a slight chance of errors in genetic testing, so it’s important to follow up with prenatal testing to confirm results.

Final Thoughts
At Boston IVF, PGT-M gives families the ability to make informed decisions about their reproductive health, helping reduce the risk of passing on genetic diseases. Whether you're dealing with a known genetic condition or simply want to improve the likelihood of a successful pregnancy, Boston IVF is here to guide you every step of the way.