What is Preimplantation genetic diagnosis (PGD)?
Preimplantation genetic diagnosis (PGD) is a highly sophisticated scientific technique developed to test embryos for specific genetic or chromosomal abnormalities. Combined with an IVF cycle, it allows for the selection of embryos that are not affected with the condition being tested for, prior to implantation and pregnancy.
For couples wanting to avoid the transmission of a known genetic condition to their children, PGD allows for the testing of single gene disorders.
For women experiencing repeated IVF failure or recurrent miscarriage, Preimplantaton Genetic Screening (PGS) screens all 24 chromosomes in a developing embryo, enabling our scientists to select only the embryos with a normal chromosome profile to transfer back to the woman’s womb, increasing the likelihood of pregnancy success.
How do we test for known genetic conditions?
A gene is a sequence of DNA (genetic material) on a chromosome with a particular function. When the DNA sequence on a particular gene is altered, a genetic abnormality such as cystic fibrosis or thalassaemia may result. It is now possible to test for many hundreds of single gene disorders with Preimplantation Genetic Diagnosis (PGD).
TasIVF provides patients with access to the very latest technology in the field of PGD, Karyomapping. Karyomapping can test for a large number of single gene disorders including:
- Huntingtons’ disease
- Cystic fibrosis
- Duchenne muscular dystrophy
- BRCA1/BRCA2 (hereditary breast/ovarian cancer)
There are some disorders where, although it is apparent from the family history that is cause is genetic, the exact gene is simply not known. In these cases, PGD using Karyomapping is not suitable. However, you will still be able to undergo PGD using the traditional PCR methodology. The PCR methodology requires the development of individual gene sequences that can be matched with the exact mutation that you are carrying.
Some people have a parent affected by a serious genetic condition, such as Huntington’s disease, that does not generally manifest until later in life. Many people do not want to have testing to determine if they have inherited that condition from their parent, however do not want to risk passing it on to their own children. In these cases, we can use exclusion testing to ensure the embryos have not inherited the ‘at risk’ gene.
Who should consider Preimplantaton Genetic Screening (PGS)?
Your TasIVF fertility specialist may recommend Preimplantation Genetic Screening (PGS), in combination with an IVF cycle, if:
- You have experienced repeated IVF implantation failure or recurrent miscarriage
- You have had a previous pregnancy affected by a chromosomal abnormality (such as Down syndrome), or
- You are of advanced maternal age (over the age of 38 years).
At TasIVF, PGS is performed using 24Sure Array CGH (comparative genomic hybridization) technology which enables all 24 chromosomes in a developing embryo to be analysed prior to implantation. This allows selection of the embryo with the greatest likelihood of pregnancy success.
Testing for a translocation
In some people, part of one chromosome attaches to the end of another, or pieces of chromosomes may break off and be swapped around so although that person has a normal complement of chromosomes their embryos could inherit missing or extra pieces of chromosome. This is known as ‘unbalanced translocation’.
Embryos with unbalanced translocations usually do not implant, miscarry or rarely, result in the birth of a child with severe abnormalities. PGD can detect unbalanced translocations, as well as errors of all other chromosomes in a developing embryo.
Can PGD be used for gender selection?
Some genetic conditions affect only one gender, for example haemophilia and muscular dystrophy. Sometimes it is not possible to detect the exact genetic error that causes the disease and PGD is used to determine the gender of embryos and any errors of all other chromosomes. Then, only the embryos of the required gender and with the correct number of chromosomes will be transferred.
Gender selection is prohibited in Tasmania for non-medical, family balancing reasons.
How much does PGD or PGS cost?
At TasIVF the cost of PGD using Karyomapping is $1,640 for the preliminary evaluation plus $700 per embryo tested with a maximum fee of $2,460 for six or more embryos from one stimulated IVF cycle.
The cost for PGD or PGD using PCR or CGH technology is $700 per embryo with a maximum fee of $3,995 per stimulated IVF cycle.
The cost of PGD or PGS is in addition to your IVF cycle cost. There is no Medicare rebate associated with embryo screening. However, your final costs may vary depending on your individual circumstances.
For more information about Preimplantation Genetic Diagnosis (PGD) or Preimplantation Genetic Screening (PGS) in Tasmania, phone TasIVF on 1800 111 483 or email us.