Preimplantation Genetic Testing (PGT-A & PGT-M)
Preimplantation Genetic Testing for Aneuploidy (PGT-A) or for Monogenic disorders (PGT-M) refers to procedures where embryos obtained through an IVF cycle are evaluated for genetic disorders prior to implantation.
PGT-M (formerly known as PGD, Preimplantation Genetic Diagnosis) was first used in 1989 and resulted in the birth of a normal female baby that was free of the specific genetic disease that was carried by the parents. Since then, many children have been born after PGT-M. Each year, the number of genetic conditions that can be analyzed by the PGT-M lab grows.
PGT-M is done when patients are concerned about passing on a specific disease or condition to their children and there is a specific gene marker or group of markers to identify the condition in the embryo. PGT-M is designed to help detect genetic abnormalities in embryos before implantation, thereby avoiding the transfer of affected embryos.
Examples of patients who may use PGT-M are those who carry genes for:
- Robertsonian and reciprocal translocations
- Fanconi’s anemia
- Sickle cell anemia
- Tay-Sach’s disease
- Cystic fibrosis
- Myotonic dystrophy
- Many many others
PGT-M involves the use of IVF to create the embryos. Each embryo then has cells removed from them in the lab and then analyzed for the genetic problem in question. Once the results of the PGT-M analysis are known, the embryos that are free of the genetic problem are chosen for embryo transfer at our fertility clinic.
PGT-A (formerly known as PGS, Preimplantation Genetic Screening)
PGT-A is an evolving technology that is being used increasingly as part of the IVF process for patients. It is used to identify embryos that may be affected by chromosomal abnormalities and involves the chromosomal analysis of the embryos generated during the IVF cycle. This way embryos that are put back into the uterus by your fertility doctor are known to be chromosomally normal. This is felt to increase pregnancy rates and reduce miscarriage rates. PGT-A also enables confident single embryo transfer, avoiding health complications associated with twin or triplet pregnancies.
Many embryos that are generated in an IVF cycle are chromosomally abnormal and if put into the uterus, will either not implant (resulting in a negative pregnancy test) or if they do implant, result in an early miscarriage. Patients of all ages make some chromosomally abnormal embryos because the abnormality arises from the eggs used. Patients have some abnormal eggs in their ovaries no matter what their age is. PGT-A is currently the only method available to determine “embryo quality.”
If you’d like more information on genetic screening, the team at RCC Fertility would be happy to help. Contact us today or request your appointment with our doctors!