Baylor Medicine offers preimplantation genetic testing, or PGT, to test embryos conceived through in vitro fertilization (IVF) for certain genetic conditions. PGT is an option available to people who are considering IVF to build a family and want to reduce the chance of having a child with one or more genetic conditions. This option allows embryos to be tested for specific genetic conditions so that this information can be used to help decide which embryos to choose for transfer in an IVF cycle.
There are three main types of PGT.
- PGT-A stands for Preimplantation Genetic Testing for Aneuploidy. Aneuploidy refers to problems with the chromosomes that can happen by chance in any embryo. PGT-A is an option available to all people, though it can be especially helpful for people over the age of 35 at egg retrieval.
- PGT-M stands for Preimplantation Genetic Testing for a Monogenic condition. A Monogenic condition is a condition associated with specific, identifiable genes. PGT-M is an option available to people who are known to be at increased risk of having a child with a specific inherited genetic condition. People often find out about this increased risk through carrier screening, or personal/family health history.
- PGT-SR stands for Preimplantation Genetic Testing for Structural Rearrangements. Structural rearrangements refer to problems with the chromosomes that can be passed to an embryo from a healthy parent. PGT-SR is available to people who carry a rearrangement in their chromosomes that puts their embryos at increased risk for specific chromosome problems.
Examples of conditions that PGT can test for include:
- Chromosome conditions (aneuploidy), such as Down syndrome, trisomy 18, trisomy 13 (PGT-A)
- Chromosomal rearrangements, such as inversions and translocations (PGT-SR)
- Autosomal recessive conditions, such as cystic fibrosis, sickle cell anemia, spinal muscular atrophy (PGT-M)
- X-linked conditions, such as fragile X syndrome, hemophilia, Duchenne muscular dystrophy (PGT-M)
- Autosomal dominant conditions, such as autosomal dominant polycystic kidney disease, Huntington disease, neurofibromatosis, inherited cancer predisposition syndromes (PGT-M)
The Baylor PGT program coordinator and the genetics team work closely with patients throughout the process of IVF/PGT. Patients initially meet with one of our genetic counselors, and when necessary, additional tests are ordered. Once all medical information and insurance details are complete, patients are able to work with our IVF team to proceed with the option of IVF with PGT. Out-of-town patients can be monitored in their home location, but biopsy and genetic analysis must be completed in Houston.