The first successful implementation of pre-implantation genetic diagnosis (PGD) was performed on women who carried an X-linked disorder called adrenoleukodystrophy (ALD) in 1990.
This progressive and incurable disorder causes hyperactivity, seizures, and severe issues with speech, hearing, and cognition. Adrenoleukodystrophy eventually leaves children in a near-vegetative state by the time they reach adolescence. By carrying this X-linked genetic disorder, the mothers’ unborn sons (females only carry the disorder) had a 50/50 chance of suffering symptoms of the disorder.
After screening embryos and selecting embryos possessing only Y (female) chromosomes, the female embryos were transferred to the uterus. The women gave birth to healthy girls and did not have to worry about ALD negatively impacting the lives of their children.
What Makes PGD Different from Other Genetic Tests?
While other genetic tests are performed during pregnancy or after a child is born, PGD tests embryos for severe genetic disorders prior to implantation in a woman’s uterus. For example, prenatal genetic testing is done between the third and sixth month of pregnancy and can detect chromosomal abnormalities indicative of Down’s Syndrome, Klinefelter Syndrome, or Turner Syndrome. Carrier and Diagnostic tests can be performed on adults and children to learn if they are “carriers” of a genetic disorder that can be passed on.
The primary advantage of PGD is that embryos can be tested before they are implanted in the uterus. This prevents a child from inheriting and possibly suffering from a serious and often fatal genetic disorder.
Who Should Consider PGD?
If you are over 35 and plan on getting pregnant, you may be at risk for having a baby with too few or too many chromosomes. Pre-implantation genetic testing is recommended for women in their 30s and 40s using an assisted reproductive technology like IVF or IUI. This ensures embryos with normal chromosomal arrangements are implanted.
People can be “carriers” of a genetic disorder but remain healthy. However, women who are carriers risk passing the disorder to their child. Women who discover they are carriers of a life-threatening, genetic disorder often opt for IVF even if they are able to get pregnant naturally since IVF allows for PGD.
How is Pre-implantation Genetic Testing Performed?
Once a fertilized egg divides multiple times to produce an embryo with eight or more cells, doctors can conduct a PGD procedure. The first step involves making a tiny hole in the zona pellucida (thick membrane) surrounding the embryo. Next, a fine tube is inserted to remove one cell. If testing is done on an embryo with over eight cells, the doctor may remove more than one cell. Genetic tests are then performed on embryonic cells. The remaining cells continue maturing naturally. Removing a couple of cells at this early stage will not harm an embryo.
Your unique genome develops rapidly as soon as sperm fertilizes an egg. At conception, chromosomes from the sperm and egg combine to complete a set of 23 pairs of chromosomes (46 in total). If an abnormality exists in any one of these pairs, the child could be born with a genetic disorder.
Important Facts to Know About Pre-implantation Genetic Diagnosis
PGD is not a procedure meant to create so-called “designer babies.” This type of genetic testing does not alter or manipulate the genome of an embryo. It is a valuable and effective technique to detect potential genetic variations passed on to an embryo.
You cannot use PGD or any other genetic test to “select” children according to intelligence, physique, eye color, or other inherited traits. Also, it is highly unlikely that genetic tests meant to screen for certain desirable traits will be available in the near future, given the genetic complexity and environmental variability of inherited traits.
Call Viera Fertility Clinic in Melbourne Today
In addition to pre-implantation genetic diagnosis testing, At Viera Fertility Center, we also provide many assisted reproductive technologies, fertility testing for men and women and many other services to help you and your partner become pregnant. Contact us today to schedule an appointment at our Melbourne fertility clinic!