PGD or Preimplantation Genetic Diagnosis refers to the process of removing a cell from an embryo for genetic testing. PGD can be one the most difficult processes for patients to understand because there are several important decision points.
Some genetic diseases with identified mutations include:
- Cystic Fibrosis
- Muscular Dystrophies
- Huntington’s Disease
- Hemophilia A
- Sickle Cell Anemia
- Tay-Sachs Disease
Couples with a previous child having a genetic disorder are recommended to seek PGD because chances of having a second child with a genetic disorder are higher.
PGD allows couples to have children without the risk of transmitting the diagnosed disorder to the embryo. This procedure can eliminate chances of having a child born with a genetic disease or suffering a late pregnancy termination due to genetic abnormalities.
PGD is done in conjunction with in vitro fertilization (IVF), by testing at-risk embryos. Embryologists perform an embryo biopsy by removing one cell from an embryo that is three days old or several cells from one that is five days old. The cell(s) are examined for the predetermined genetic abnormalities. We only transfer embryos deemed free of having a genetic abnormality into the woman.
The sex of the embryo can also be detected through PGD. Some genetic disorders are only transmitted to a certain sex, males (sex-linked mutations located on the X chromosome of the mother). An example of this is Duchenne muscular dystrophy, which is only transmitted to male embryos. Limiting embryos transfer to female embryos can be part of the strategy to avoid disease in the child.