Pre-implantation Genetic Diagnosis (PGD)

Introduction

All couples hope to have a healthy baby. For some couples at risk for passing on a severe genetic disorder, this wish is major concern. Fortunately, if you know that you carry a gene for a serious illness, it may be possible to screen for the gene and help reduce or eliminate the risk of your offspring being affected with the illness.

In the past, couples with genetic disorders were only able diagnose the health of their unborn child during pregnancy by techniques such as chorionic villus sampling and amniocentesis. Consequently such couples faced a high risk of having to decide whether they would end an established pregnancy. Through Monash IVF we are able to offer Pre-Implantation Genetic Diagnosis PGD for couples who carry genes for certain serious inherited disorders.

Pre-implantation genetic diagnosis (PGD) is a technique that enables couples at risk of passing on a genetic disorder who undergo in-vitro fertilization (IVF) to have their embryos screened before a pregnancy is established so that only healthy embryos are selected to be transferred into the woman's uterus. PGD can be used to screen for known single gene disorders, translocations, and some of the more common chromosomal abnormalities such as Down Syndrome.

The results obtained from PGD are approximately 90% accurate if you have PGD for chromosomal screening and up to 98% accurate if you undergo PGD for a specific genetic condition. Therefore, there may be up to a 10% error rate associated with any test performed. Because of this, in pregnancies that result from PGD treatment it may be necessary to consider prenatal diagnosis using either chorionic villus sampling or amniocentesis.

What does PGD involve?

PGD involves an IVF treatment where the woman's eggs are fertilized outside her body in the laboratory. Embryos then undergo biopsy and the resulting cells are screened for the specific genetic marker using a polymerase chain reaction (PCR) or fluorescent in situ hybridization (FISH). This screening identifies which embryos are healthy, from which we choose the embryo to transfer on day five.

Genetic Conditions Eligible for PGD

PGD is for couples where one or both partners carry the genes for a serious inherited disorder such as:

A balanced translocation
Huntington's disease
Thalassemia
Cystic fibrosis
Marfan's syndrome

These are examples of disorders eligible for PGD, and there are over 100 genetic disorders in which using PGD can be helpful.

Important Points

Before considering PGD, it is often advisable to undergo genetic counselling so that you are fully aware of the details of your situation and of your options. PGD is a complex and expensive process that requires couples to undergo in-vitro fertilization which they may not otherwise need. There is a risk that there will be no surviving, unaffected embryos for transfer. Usually, eligible couples must have a known genetic disorder. We can't screen embryos for unspecified abnormalities. Australian law prohibits PGD for gender selection for social reasons.

Further information

A copy of our PGD Fact Sheet can be downloaded from the bottom of this page. Please feel free to contact Bubtree or Monash IVF for more information on PGD.

PGD Fact Sheet - 128 KB