What it is
For people who know they are at increased risk of passing on a specific genetic condition, PGD, or preimplantation genetic diagnosis, can be performed prior to pregnancy to greatly reduce the risk of having an affected child. PGD for single gene disorders involves testing embryos created through in vitro fertilization (IVF) and then transferring unaffected embryos.
WHO IT’S FOR
PGD is appropriate for people who are at high-risk of passing on a specific single gene disorder. You may consider PGD if:
- You and your partner are carriers of the same autosomal recessive condition (e.g. Cystic fibrosis)
- You are a carrier of an X-linked condition (e.g. Duchenne Muscular Dystrophy)
- You or your partner have an autosomal dominant condition (e.g. Huntington disease)
- You or your partner have a mutation associated with a hereditary cancer syndrome (e.g. BRCA1 & 2)
- You had a child or pregnancy with a single gene disorder
- You want to perform HLA matching
How it works
PGD tests are created uniquely for each family. PGD can be performed for nearly any single gene disorder as long as the specific familial mutation has been identified and appropriate family members are available for test preparation.
*Internal CooperGenomics data
The PGD Process
1. Case Review
Prospective parents speak with a genetic counselor and discuss if additional genetic testing of the couple or other family members is required.
2. PGD Test Preparation
The PGD lab designs a test unique to each family.
In vitro fertilization is performed and the resulting embryos are incubated.
4. Embryo Biopsy
An embryologist carefully removes a small cell sample from each embryo.
Samples are sent to the PGD laboratory, testing is performed, and results are released to the IVF center.
6. Embryo Transfer
An unaffected embryo is transferred. Remaining embryos can be frozen for future use.
PGD testing involves a close examination of both the mutation an individual carries and the area of the chromosome surrounding it, shown above as the colored segment of each chromosome. Each PGD test design is unique and specific to the family, so DNA samples from both partners, and often additional family members, will be requested in order to design a test. Then, linkage analysis is used to determine the “genetic fingerprint” of the mutation and diagnose each tested embryo as affected or unaffected.