Preimplantation Genetic Diagnosis (PGD)
Preimplantation Genetic Diagnosis
We are often able to determine if a particular embryo is carrying a specific genetic disease. Through preimplantation genetic diagnosis (PGD), an embryo can be biopsied and the removed cells can be analyzed for a specific genetically transmitted disease. This enables patients to greatly reduce the likelihood of passing on a genetic mutation to their offspring.These embryos are derived from the In Vitro Fertilization process.
Partial List of conditions that PGD can detect:
- Cystic Fibrosis
- Duschenne Muscular Dystrophy
- Retinitis Pigmentosa
- Charcot-Marie-Tooth Disease
- Alpha-1-Antitrypsin Deficiency
- Down's Syndrome
- Fragile X Syndrome
- Lesch-Nyhan Syndrome
- Turner Syndrome
- Huntington's Chorea
- Phenylketonuria (PKU)
- Gaucher's Disease
- Sickle Cell
How is PGD Performed?
PGD testing is performed on embryos that result from In Vitro Fertilization. Multiple eggs are retrieved from the ovaries and fertilized with the partner's sperm in our lab using a technique called ICSI. Five to six days after fertilization, when each surviving embryo, now called a blastocyst, contains hundreds of cells, 4 to 6 cells are removed from the trophectoderm (placental cells) through a procedure called embryo biopsy. The biopsied cells are then sent to a specialized lab for genetic analysis using various tecniques depending on the genetic mutation being evaluated. The blastocysts themselves are frozen after biopsy while we await the results of the genetic testing. Those that are normal (nonaffected or carriers)can be thawed in the next cycle during a frozen embryo transfer. Frequently, PGD and PGS are performed in unison on embryos.
Who should have PGD?
PGD has revolutionized the management of patients at risk for passing on an inherited genetic disease due to a single gene defect. PGD dramatically improves the odds of having a baby without the disorder since affected embryos are identified and not transferred. Some disorders only affect male offspring, so that female embryos may be selected to avoid the condition even if the exact defect isn't understood. Please call our office to learn more about these exciting clinical tools.