How does Preimplantation Genetic Screening work?
Screening for several genetic disorders is performed before the transfer of healthy embryos to the female.
Thanks to Preimplantation Genetic Screening, genetic disorders like Down's syndrome, Monosomy and Trisomy can be screened.
Chromosomes (13, 15, 16, 17, 18, 21, 22, X, Y) are checked in PGD-9 testing and with NGS or aCGH, the complete chromosome set can be screened. Since gender chromosomes are also screened, gender selection can also be performed on cases where some genetic anomalies can pass via the gender chromosome or if patients are looking for family balancing.
What are the methods used in Preimplantation Genetic Screening? We briefly though on the most popular methods used currently and in recent times. These include:
Fluorescent in situ Hybridization (FISH)
FISH came to be in the late 1960s, but never actually came into use until the 1990s. It's very powerful, but also relatively limited in scope. For example, FISH is only capable of being able to be used on common abnormalities such as chromosomes 13, 15, 16, 17, 18, 21, 22, X and Y in a diagnosis.
As such, it lacks the scope of newer techniques like NGS and aCGH.
However, for the purposes of gender selection, this method can be used.
Array Comparative Genomic Hybridization (aCGH)
Normally, aCGH would be a good choice as it can target particular sets of DNA so would make sense for looking at conditions you know you have. It's very fast, it's quite precise with much lower error rates in general, making it great for pinpointing exact genetic disorders.
However, it does struggle with finding some problems that would be important in gender selection, and it also cannot detect anything you aren't directly searching for as prior knowledge is needed in the assay design.
Next-Generation Sequencing (NGS)
NGS is another potent method and is used to help locate chromosomal abnormalities. By looking across millions of fragments parallel with one another, there is a much higher level of data generated than with older modules such as Sanger sequencing.
NGS allows for the screening of the complete chromosome set and is one of the latest technologies currently available.
If further reading is required, you can learn more about PGD testing in this article here.
Who would choose to use PGD treatment? Is testing ethical?
With PGD, it is also possible to detect numerical chromosome anomalies such as Monosomy or Trisomy, such as Down Syndrome & other Trisomies. Indeed, PGD testing could even be used for Single Gene Disorders, such as:
- Cystic Fibrosis.
- Haemophilia A1 and B1.
- Muscular Dystrophia.
- Sickle cell anemia & Fanconi anemia.
PGD/PGS success rates
Couples usually proceed with Preimplantation Genetic Diagnosis or Preimplantation Genetic Screening (PGD/PGS) to avoid having a baby with genetic abnormalities.
Based on the recent researches, the use of PGS/PGD testing enables to increase pregnancy success rates and live birth success rates due to the reason that transferred embryos don't have any chromosomal abnormalities which also reduce the risk of miscarriage.
The accuracy (correctness of genetic testing) is 99.9 %, therefore the chance of missing a genetic anomaly after performing the test is very low.
If the possibility exists to overcome conditions that might have made conception difficult, then it makes sense for PGS/PGD to have the chance to increase success.
Advantages of PGD in Cyprus
Some of the benefits which can derive from taking part in PGD would include:
- Increase in the implantation rate with the transfer of healthy embryos in cases with repetitive implantation failures.
- A decrease in the need for multiple pregnancies to finally achieve success.
- Prevention of abortion due to the transfer of healthy embryo before pregnancy occurs.
- Increase in the clinical pregnancy rate thanks to high standards of care.
- Baby's gender selection before pregnancy due to medical reasons.
- Popular with those who of advancing years who wish to avoid more miscarriages.
- Avoiding genetic anomalies in the family.
What is the typical PGD cost?
Normally, the cost of PGD treatment would start from €5,500.
With newer methods like NGS, there are additional costs per embryo tested. Other IVF treatments costs can be found here.
However, such costs may change and vary significantly depending on the circumstances you would undergo personally. The typical question, though, of how much does PGD cost, is that you would expect your fees to start at the above figure.
There are many other genetic tests that can be performed and as such the method and the cost should be discussed with the medical facility.