Preimplantation Genetic Diagnosis
If you have a child or family member with an inherited genetic disorder, or if you and your partner are carrier for a genetic disorder, you may be interested in your options for having children free of this condition. One option available is in vitro fertilization (IVF) with preimplantation genetic diagnosis (PGD). PGD enables testing of an embryo for a specific genetic disorder prior to pregnancy, thus significantly reducing the chance that a resulting baby will have the disorder.
How is single gene PGD plus Parental Support different?
The biggest problem with single gene PGD is the chance of misdiagnosis. Misdiagnosis can occur for many reasons, the main reasons being:
- Allele Drop Out (ADO): PGD testing requires more DNA than is available from the single cell or cells removed from the embryo. To create more DNA, a laboratory technique called “DNA amplification” is used. ADO occurs when the section of the DNA contacting the gene mutation does not copy correctly. ADO is a normal by-product of the DNA amplification process and affects all types of PGD testing.
- DNA Contamination: This occurs when non-embryonic DNA gets mixed into the sample
- Extra or missing copies of the chromosome carrying the gene mutation: This can result in misdiagnosis of the gene status.
Parental Support combats these problems by sing a microarray testing platform plus Parental Support bioinformatics:
- Approximately 35 small sections of DNA called ‘markers’ surround the mutation are evaluated to address ADO. Other PGD methods typically evaluate only 2 to 6 markers.
- All embryo samples are matched to DNA samples taken from the parents to confirm that the DNA being tested is from the embryo and not due to contamination.
- The entire chromosome carrying the gene mutation is evaluated to make sure there are exactly two copies before making a diagnosis on gene status.
- In this way Parental Support provides the most accurate PGD test results available, typically greater than 99%. In addition, every Parental Support PGD test includes Trisomy 21 screening to reduce the chance of Down syndrome.
How is PGD performed during an IVF cycle?
- PGD is usually performed on Day 3 after fertilization when a single cell from each embryo is removed and tested.
- Using a newer biopsy technique, PGD can also be performed on Day 5 by removing and testing a few cells from each embryo. With both Day 3 and Day 5 testing, embryos are frozen until test results are returned. They are then thawed and transferred in future IVF cycle.
PGD Plus Parental Support gives you:
- Highly accurate test results – typically greater than 99% for single gene testing
- Routine screening for Trisomy 21 (Down syndrome) included with all single gene testing
- Option of concurrent 24-chromosome screening to reduce chance for other chromosome abnormalities and possibly increase chance for pregnancy.