Preimplentation Genetic Diagnosis and Screening (PGD) (PGS) prevents the transmission of genetic diseases and helps balance families through gender selection.
Reproductive Care Center is able to screen for more than 120 specific genetic diseases such as Tay Sachs, cystic fibrosis, Fanconi anemia, fragile X syndrome, hemophilia A, and others. As more genetic diseases are characterized, they are added to the list of those which can be screened.
The risk of genetic disorders is directly related to the female’s age. Women over 35 are at a higher risk for chromosomal abnormalities which can lead to early miscarriage or conditions such as Down’s syndrome. PGD testing helps reduce these risks.
Overview
Preimplantation genetic screening (PGS) provides a means to screen embryos for abnormalities in chromosome number prior to uterine transfer in an IVF cycle. PGS is also an extremely accurate method for identifying male and female embryos making gender selection, or family balancing, a scientific reality. Many patients want to experience the joy of raising children of both genders.
Process
1
Testing
One or two cells are removed from the embryo for DNA testing using either FISH and/or PCR. Cell biopsy does not typically damage the embryo. Test results are usually available within 48 hours.
2
FISH (flourscent in situ hybridization)
Chromosomes from the embryo are labeled with fluorescent tagged probes and are examined under a special microscope. These tags allow gender determination, identification of missing or extra chromosomes, and translocations.
3
PCR (polymerase chain reaction)
PCR creates multiple copies of specific identified areas of the chromosome and is used to screen for single gene defects. When the genetic disease is present in the parent, a copy of a segment of his/her gene can be used to make a genetic probe. This probe will “identify” the genetic disease if it is present in the embryo.
4
Transfer of Embryos
Healthy embryos are transferred into the uterus using IVF.
Conditions
PGS prevents the transmission of the following genetic diseases
Hemophilia
Genetic disorders such as hemophilia can only be present in a child of a particular sex. For example, hemophilia A and B are X (female chromosome) linked recessive and can only occur in males (XY). If a woman has the gene for hemophilia, after PGD, only female embryos are transferred to the uterus eliminating the chance for hemophilia in the baby.
Tay Sachs
A rare, inherited disorder that destroys nerve cells in the brain and spinal cord.
Cystic Fibrosis
An inherited life-threatening disorder that damages the lungs and digestive system.
Multiple failed IVF cycles for unexplained reasons
Fragile X Syndrome
A genetic condition causing intellectual disability.
