Preimplantation Genetic Diagnosis/Screening (PGD)(PGS)
Finding Out Before
Preimplantation Genetic Testing are state of the art procedures used in conjunction with in-vitro fertilization to help select embryos free of chromosomal abnormalities and specific genetic disorders for transfer into the uterus. Indications include recurrent miscarriage, advanced maternal age, and inherited genetic disorders.
How does PGD work?
For patients who are at high risk of having offspring with genetic abnormalities, they may elect to undergo PGD. There are currently hundreds of diseases that can be tested for in couples interested in conceiving, that typically screen for what’s called ‘recessive gene mutations’. If a couple happens to be a known carrier of certain gene mutations, such as cystic fibrosis or muscular dystrophy, embryo screening can be done to ensure that disease is not passed on to offspring. This is only done for recessive gene muations if both partners carry a mutation for the same disease, because if only one partner carries a gene mutation, it poses no risk to their offspring. PGD is performed as part of an in vitro fertilization cycle. An embryo biopsy is performed to removal a few cells from each embryo that has grown in culture for 5 days. It typically can take about two weeks for the results; thus, embryos will be transferred in a frozen embryo transfer cycle the following month.
What other types of chromosomal testing can be done on embryos, and what is PGS?
In a normal embryo, there are 23 pairs of chromosomes, either 46XX or 46XY. As women age, the risk of having chromosomal abnormalities in the embryo increases. One of the most common abnormalities is Down’s syndrome, a condition having 47 chromosomes including an extra chromosome 21. The current technology allows us to evaluate an embryo and confirm that there is a normal number of chromosomes prior to placing it back into the uterus. This is called Preimplantation Genetic Screening (PGS). IVF success rates are increased, and miscarriage rates are significantly decreased, due to the transferring of genetically normal embryos.
Is there an additional charge for PGD or PGS?
Although the biopsy is performed at our center, the testing is performed elsewhere at a special laboratory. The outside laboratory does charge an additional fee for their services and this fee varies depending on the type of testing being performed.