Pre-implantation Genetic Diagnosis

 

Source

 

 

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My Stance:

Preimplantation Genetic Diagnosis is a great tool. It helps to determine risks and prognosis of diseases such as Cystic Fibrosis. However, there are some risks, and not all is known yet about this type of testing. It is for this reason that I believe it should be used, but with caution.

 

What is Preimlantation Genetic Diagnosis?

 

PGD is a type of genetic test. According to Webster’s Medical Dictionary, genetic testing is “Tests done for clinical genetic purposes. Genetic tests may be done for diverse purposes pertaining to clinical genetics, including the diagnosis of genetic disease in children and adults; the identification of future disease risks; the prediction of drug responses; and the detection of risks of disease to future children.” So, PGD is a test used to determine the risks of future illness and disease, before the baby is born. PGD is performed after an embryo has reached the full 8 cell stage. They then remove one cell, which they use to test for diseases such as Cystic Fibrosis, and other ailments.

 

This is as example of an 8 cell embryo, before PGD is performed:      

http://www.infertile.com/treatmnt/treats/pgd.htm

Figure 1: 8 Cell Embryo Ready for Biopsy (i.e. Remove One Cell)

 

                                                                                                                               

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The egg and the sperm are collected, and put on a Petri dish. The following morning the eggs are examined for fertilization. Once that occurs a cell is removed from the embryo and is tested. The embryo is still able to grow, and this allows parents to know whether their child has the gene for any medical conditions, like cystic fibrosis.

 

Here is a diagram of the PGD process an embryo goes through

Click to see larger picture

http://www.emedicine.com/med/topic3520.htm

 

 

 

Pro/Con

There are reasons both good and bad for PGD.  One pro is that PGD is used to discover genes for many types of diseases. But, there are risks because Another pro is that it helps determine a child’s risk for Cystic Fibrosis. However, if too many cells are removed, it could lead to complications after birth.

 

History

The following is a brief timeline, illustrating the history of Cystic Fibrosis:

To find out more information, click here

Middle Ages- infants with salty skin, a symptom of Cystic Fibrosis, said to be “bewitched.” Excessive salt in the skin is a symptom of CF. Excessive amounts of salt can cause abnormal heart rhythms and shock.

1936- Condition is named as Cystic Fibrosis, before this the condition had no name. This helped put a name to the condition many people faced.

1938- First list of Cystic Fibrosis symptoms is created. This was created by Columbia University. This helped people identify Cystic Fibrosis in others.

1953- Sweat test, now the most common test, is developed after a heat wave occurred in New York City. Since this, the sweat test has become the most widely used form of detecting Cystic Fibrosis. It measures the amount of salt in the sweat.

1968- the first embryo biopsy was performed on a rabbit. PGD for cystic fibrosis came into play around the 1980’s. The first human to have PGD performed was in the United Kingdom in the 1980’s. The gene for Cystic Fibrosis was discovered in 1989.

Mid 1980’s- PGD for humans first developed in the United Kingdom

1989- Discovery of the gene for Cystic Fibrosis, cystic fibrosis transmembrane conductance regulator, known as CFTR. A hospital in Toronto discovered this gene, which is one step further in knowing more details about this disease.

1990- Britain passes the Human Fertilization and Embryology Act

May 2001-current-About 30,000 Americans are said to have Cystic Fibrosis, this is according to the Cystic Fibrosis Foundation.

 

Human Fertilization and Embryology Act 1990

 

This act is from the United Kingdom. It came about as a way to make provisions to a previous law. This act helped to explain what the government’s job would be in relation to things like in-vitro fertilization, and other things in relation. It details what a person can and cannot do, and explains in detail what a gamete, an embryo, and other related terms are. This Act gave the Government the authority to observe and keep a record of what happened to the embryos after being tested, and so on. This act occurred only about 2 years after the discovery of the gene that causes Cystic Fibrosis. According to the Act, it was created “to make provision in connection with human embryos and any subsequent development of such embryos; to prohibit certain practices in connection with embryos and gametes; to establish a Human Fertilization and Embryology Authority; to make provision about the persons who in certain circumstances are to be treated in law as the parents of a child; and to amend the Surrogacy Arrangements Act 1985”

http://www.opsi.gov.uk/acts/acts1990/Ukpga_19900037_en_1.htm#tcon

 

In the United States, laws related to In Vitro Fertilization vary depending on the States. Many States have laws relating to insurance coverage as well, but one would have to look into the State the live in to find out more information. (click here for more information)

 

                                                                                                                                                                                                         

Video:

The following link is a video interview done by the NBC station in St Louis, with the man who helped discover the gene and so on for pre-implantation genetic diagnosis. He details how he came about it, what happens during the testing, and mentions whether it is a good or bad idea, in his opinion:

Pre-implantation Genetic Diagnosis (PGD) - Video Clip

The testing is very useful in finding out the risks the baby may or may not have which the parents may or may not want to go through with the pregnancy as a result of this information.

Some Questions Raised:

*          Why is sweat salty in CF patients?

*          Each of us has a certain amount of salt within our bodies. Those with more salt then the normal amount usually have cystic fibrosis   

*          How can diet help CF patients prolong life?

*          Maintaining a healthy lifestyle, eating good foods, such as vegetables increases the person’s life. This is not a cure, it just helps maintain the person’s health and well being.

*          Is there any cure for CF patients?

*          There is no real cure for CF. Daily treatments such as chest  

*          For more information, click here

Why does it matter?

So, why does all this matter to you? It matters because this will affect the future of medicine and families. This will cause people to have babies, knowing the risks the child has for CF and other diseases. This information has led to aiding many in deciding whether to have a child. Cystic Fibrosis is a serious condition, and some may not want to put themselves or a child through the difficulty with this type of condition. However, many people live seemingly normal lives, despite Cystic Fibrosis. The life-span for those with CF has increased, since the early years, and this has a lot to do with the medical treatments we now have. I do not think that when a parent has PGD performed, and finds the child may have CF, it should not automatically mean they should terminate the pregnancy. PGD is something that each person should make there own decision in whether it is okay or not to do. There are too many personal ethical issues involved for me to say a definite answer as to whether a person should or should not have PGD performed. One has to come up with their own judgment call as to whether they would or would not have this testing done.

 

Miscellaneous

The following are examples of the projects and assignments Dr Demers had us complete in the process of creating this website. I also included a link to the course website for you to find further information on the course, and what the class is about.

Course site

 Timeline

Annotated bibliography

Evaluating websites

Mining resources

Outline