Preimplantation Genetic Testing
Be in the Know. Preimplantation Genetic Testing (PGT & PGT-M) at a Glance.
- Preimplantation genetic testing (PGT) of embryos has made tremendous advances since its introduction in 2005. Although genetic testing could be performed on human cells before 2005, techniques were developed to perform genetic testing on just a few cells removed from a developing embryo.
- Genetic testing allows prospective parent(s) undergoing in vitro fertilization (IVF) to test for a specific gene or for chromosomal copy number abnormalities before transferring the embryo into the uterus. This can increase pregnancy rates and decrease miscarriage rates.
- Chromosomes are structures found in the center of the cell nucleus. A human typically has 23 pairs of chromosomes, for a total of 46 individual chromosomes. An embryo receives 23 chromosomes from the sperm and 23 from the egg. Chromosomes are made up of genes, which contain the genetic information that instructs the body on how to function.
- Embryos can be tested prior to an embryo transfer for their chromosomal copy number or rearrangement (preimplantation genetic testing – PGT) or for a specific singe gene mutation (PGT-M).
- This testing is performed on cells from an embryo biopsy on the 5th or 6th day of embryo development. Embryos are frozen, or “banked,” until results of the genetic testing are available.
- Embryos that are identified to have the correct number of chromosomes (euploid) and/or do not carry the specific mutation tested for (“unaffected”) can then be transferred into the patient in a separate FET (frozen embryo transfer) cycle.