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. It allows us to select 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 with Karyomapping at Melbourne IVF allows for the testing of single gene disorders.
For women experiencing repeated IVF failure or recurrent miscarriage, Embryo Screening at Melbourne IVF 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 uterus 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) using Karyomapping.
Melbourne IVF is the first fertility clinic in Australia to use Karyomapping technology, a new platform that can develop the test for couples with a known genetic condition in weeks, rather than months like previous PGD technology. Karyomapping technology is a significant advancement if you want to avoid the transmission of a known genetic condition to your children. Find out more about PGD with Karyomapping »
Watch James and Natalie's story of having a baby without a known genetic condition, Huntington's disease, with the help of the Melbourne IVF pre-implantation genetic diagnosis (PGD) program.
Who should consider Embryo Screening?
- A previous pregnancy has been affected by a chromosomal abnormality (such as Down syndrome)
- You have experienced more than three consecutive miscarriages
- You have experienced repeated IVF failure (where 5 or more embryos have been transferred without pregnancy)
- You are of advanced maternal age (over the age of 38 years)
Find out more about Embryo Screening »
What is exclusion testing?
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.
PGD with Karyomapping can be used to perform exclusion testing. In exclusion testing the genetic error is not tested for but embryos are tested to make sure they have not inherited the ‘at risk’ gene from the member of the family who has the condition.
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 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 Victoria for family balancing or anything other than medical reasons.