Preimplanation Genetic Diagnosis

Preimplanation Genetic Diagnosis (PGD) is the cellular and molecular screening which determines if the In-vitro fertilized embryo will be used in the uterus.

PGD is available since the early 90es and since then PGD was performed on more than 15000 children. It is mostly used to identify hereditary diseases and anomalies. Also the gender can be determined by this diagnosis.

Before making the decision to undergo such procedures parents are advised to get a genetic screening to evaluate the risk of transferring the genetic disease to their offspring.

When parents make the decision to use PGD they will have to go through an In-Vitro fertilization, which means that an egg cell will be taken and fertilized outside of the body.

After that the egg will be kept under certain conditions so that the embryo will develop in to the cleavage stage embryo. At the third day a single blasphomere is removed from the cells for the genetic diagnosis. At this point it will be ascertained which embryo will be used.

The embryos which does not show any abnormalities will then be planted in to the uterus. (Molina B Dayal)

The conditions which are diagnosed by PGD are Sex linked diagnosis, which accrues when the mother is a carrier of the disease and could transfer the disease over the X-chromosome to a male offspring. There is also a 50% chance that if the embryo turns out to be female that this child also will be carrying on the disease.

Another condition which is diagnosed by PGD are single gene defects. Under this are falling diseases which are transmitted over only one gene.

The last condition is chromosomal disorder which is a chromosomal rearrangement or translocation which leads for example to miscarriage.

People who benefit from it are for example woman in advanced maternal age because the risk of having an abnormality is rising with age.

Also couples with a history of miscarries benefit from PGD. However PGD does not improve the pregnancy rate but increases the likelihood of pregnancy at term.

Another group which profits from PGD are man with infertility. The risk of chromosomal abnormalities rises with the condition of sever infertility. (Molina B Dayal)

Objectors however argue that all the fertilized eggs could develop into a baby under the right conditions and that it is unethically that the unsuitable egg cells will be destroyed.

One main argument that religious people bring up is that life starts at conception and destroying the unwanted egg cells is equal to murder.

Others argue that the disorder will not develop by 100% chance and that most diseases will develop at an older age and that at that time a cure might be found.

Others again are afraid that PGD could develop into producing babies which will be used as spare parts. (B.A. Robinson )

Even though that I think that some of the concerns are justified I still think that the advantages outweigh the disadvantages.

For example, nowadays the most common procedure used to check for abnormalities is prenatal diagnosis. First this procedure itself can cause harm to the unborn child and secondly if at this point of time an abnormality is diagnosed, the parents are left with the struggle to choose if they want to abort the child. So at this point I do not understand the objectors because aborting a child at this developing stage is worse than checking beforehand, because at this point of time there is already a developed baby present and the screening itself could already harm the baby.

Also I think parents want to give their child the best starting conditions, so how does someone wants to refuse this wish to the parents?

In my opinion an additional argument to that is that if parents already know about their condition, does someone want to force them to leave their child into their fate?

As well one of the biggest advantages is that some of the recent diseases could be extinct with a regular practice of PGD. Some people might say that it is against nature but no one ever had an accurate definition of nature. So is using medication and changing life so nowadays people can reach the age of 80 also against nature?

And do we really have to put people thru the struggle to live with this kind of abnormality to “protect” nature?

Also the argument of killing a human being when destroying the unsuitable embryos is not valid in my opinion. People might argue with this because of their religious believe but the start of live needs a scientific definition. So in my opinion there could be two starting points of live, the heart beat which starts after the third week after fertilization or the brain activity which accrues at first at the brain stem at the 54 day.

So by this definition there is no live after fertilization so thereby there is no dead by disposing the unsuitable egg cells.

I do agree that humanity has to be careful about choosing the right path and how we will use this procedure in the future. But at this point of time the preimplanation genetic diagnosis is the best alternative which is available.

Molina B Dayal, „Preimplantation Genetic Diagnosis“, December 30, 2015,

http://emedicine.medscape.com/article/273415-overview

B.A. Robinson , „Pre-implantation genetic diagnosis (PGD) & haplotyping (PGH)Current status; Objections; Advantages“ , September 20, 2007, http://www.religioustolerance.org/abo_pgd2.htm