Genetic Screening

Gina Larsen

Copyright 1996

Five year old Jacob Turner is a healthy boy without many cares in this world. His father takes sole care of him because his mother died suddenly. Genetic testing after death, showed a genetic mutation in Jacob's mothers genes that caused her to have an irregular heart. Unfortunately, Jacob has also inherited this mutation, but fortunately, this disorder can be controlled by medications. Now, Jacob's father has another problem. No insurance company will cover young Jacob because of his known heart irregularity.

Situations like Jacob's are now a relatively common with the advent of genetic screening. People can now look into their genetic make up to find out if they carry a deleterious gene or genetic predisposition to a disease. No longer must many people with high risk families worry about whether or not they may contract the same disease as their ancestors. Diseases and disorders such as Huntington chorea, Alzheimer's, Multiple Sclerosis, Muscular Dystrophy, Hemophilia, and some kinds of cancer such as breast, colon, thyroid, ovarian, and skin can now be identified on a particular gene and can likely predict the probability of disease onset. But with this technology comes many physiological and ethical problems. Within this paper, I will define genetic screening, look at the controversial ethical viewpoints, and give a brief overview to this situation.

Genetic Screening is a relatively new concept that is just now becoming more widespread. In simple terms, the process uses techniques that enable the technician to identify mutant DNA in the person's genetic make up. If a mutant is found, medical precautions can be taken. If none is found, then it can be assumed that the person does not carry the deleterious gene and has the same risk of contracting the disease as anyone else in the population.

The screening requires that a tissue sample be taken from the individual to be tested. Where and what kind of tissue depends on the condition being screened. When screening for a specific cancer, tissue of that organ is most helpful. When screening for a noncancer disease, blood or urine will produce results. Because the tissue sample is small, a process called Polymerase Chain Reaction (PCR) is used. PCR is a technique that enables more than a million copies to be made from a single strand of DNA. This can be done in a precancerous or cancerous cell. The copied DNA can then be hybridized. The double stranded DNA becomes separated, and can then be exposed to a molecular probe.

In the screening process, many diagnostic techniques are used. They include: DNA probes, Restriction Fragment Length Polymorphism (RFLP) analysis, and mono- or polyclonal antibodies. DNA probes are used to find and identify the gene being examined. The use of probes is used in conjunction with the use of RFLP. As the name says, this technique uses enzymes to restrict and cut the suspected gene into smaller parts near the known or suspected location of the disorder. Each of these fragments have their own identifiable pattern because of the fact that each person has homologous chromosomes given by the parents of that individual. It is these fragments that are called RFLP's. The pattern associated with the RFLP is called the genetic marker. These are the areas that can be made vulnerable to the identification of probes. Electrophoresis is the process in which the gene fragments are measured. Each gene fragment has a charge related to it and when put in an aqueous bases will move a certain amount, depending on the size of fragment, when an electrical charge is applied . The pattern shown by the electrophoresis is unique to each individual person. Electrophoresis and use of probes can identify known mutant genes that cause the disease screened. These probes consist of a single strand of DNA that is to be known as a specific mutation found in the disease. This mutation binds to the complementary genetic mutation sequence if found. Because the probe can be labeled with a fluorescent dye to attract light, it can be easily found by the technician.

Antibodies can also be used in the process. The antibodies each look for and bind to specific protiens even if that protein is in very small quantities. It is this property that is beneficial for its use as a probe. This testing can be done either within or outside of the body. The use of monoclonal antibodies can even be used to determine the compatibility of tissue in a tissue transplant. They can also be used to stimulate the growth of a tumor on a laboratory setting that would allow for better research of cancer treatment and causes.

The above technology has been in practice for many years in various forms. Every hospital in the United States screens newborns for PKU, a disorder that prohibits the child to digest the amino acid Phenylalanine. This disorder can be monitored by strict dietary means and is usually not fatal if treated correctly but can be fatal if not discovered and can cause a painful death of starvation to the newborn. It was for diseases like this that this technology was invented and put into practice. Governmental and private funding has allowed the research to continue and has now grown so that most disorders can be predicted with reasonable accuracy. The research still continues, but with it comes a considerable number of issues. Regulation, cost, social risks, religious, ethical, and medical guidelines are just some of these. Along with these issues is the fact that further technologies such as gene therapy and genetic engineering may be able to change the medical, legal, and moral system.

The new technologies bring in new responsibilities. Who should be tested and why. Currently, most doctors and researchers are saying that only those who have a familial risk should be tested and for that disorder only. Because of cost, this has mostly been the case. Screening for just one gene can range in price from $300 to $2000. This alone prohibits most people from having unnecessary screening, but it also keeps the poor from being able to be screened. Just as the poor are not able to undergo the screening, the more wealthy can afford it, and can conceivably be able to screen for disorders not familial and can thus determine the risk of that disorder.

Cancer can be used as an example. It is thought that only 5 to 10% of cancers are inherited, but the mutations can still be screened for and found. This also raises the question if such a low number of cancers are inherited, why be tested for cancer. Cancer testing, in essence, is a crap shoot in finding predisposition. Disorders such as Huntington chorea or cystic fibrosis, when found, is for the most part absolute in a diagnosis. It is because of this that cancer testing can be considered more controversial.

Also, if the screening shows a deleterious gene, further medical attention will eventually be needed. The treatment of cancer is far different than that of cystic fibrosis. With cancer, the removal of the proposed organ or tissue can totally eliminate the risk, but such is not the case with most others. Insurance companies like the idea of a one time removal of a precancerous tissue compared to the long term medical bills of Huntington chorea. Thus, if the insurance company has knowledge of the genetic screening, it may refuse coverage to someone with the possibility of onset of a disease.

Religion also has its problems with the process. It can be argued that God gave you those genes, so who are we to change them. Also and most controversial, is the fact that screening can be done prenatally. Before the birth of a child, the fetus can be tested for conditions such as sex, Down syndrome, and abnormal chromosomal numbers that lead to other disorders. Lesch-Nyhan disease is another. This disease has an onset soon after birth and causes intense pain and severe retardation to the child that can lead to violence and self mutilation and eventually results in death. The parent has the choice of either aborting the fetus or allowing the child to suffer horribly in its short life. In the most extreme case, a parent could abort the fetus because it is of the wrong gender. But on the other hand, it can also prepare the parent if the child is born with Down syndrome, allowing them to act upon the situation after birth.

As mentioned above, each child in the United States is tested for PKU following birth. This is done by cutting the heal of the child to draw the blood needed for the test. The question is now, what happens to that sample. Supposedly, that sample is thrown out, but if that sample was given for further screening, that child could be denied insurance without ever leaving the hospital.

Such problems which were unheard of just a couple of generations ago are now common. Most people agree that genetic screening is beneficial in the cases of PKU and other inherited disorders or some cancers, but draw the line at other, more ethically vague areas, such as prenatal screening. Most states have passed legislation preventing insurance companies discriminating on the basis of genetic background, and the Americans with Disabilities Act prohibits companies from denying a person employment because of genetic disposition, but legislation is slow in regulating and large corporations are fast in finding loop holes.

Personally, in my own life, I see the ramifications of such technology, both good and bad. Such techniques can lead to cures and treatments of untreatable diseases such as Alzheimer's. It can allow the patient and the family time to react to the situation and to get help in handling it. I can relate to those who do not want to know, because I don't think that I would want to know, but I think that each person should have the right to make the decision for themselves. No insurance company or business should have the right to decide for me, and my records should be sealed unless I wish them to be opened. This is not an easy view to hold, as the business world would wish it to be the other way as with less privacy and more corporate knowledge of genetic testing, but until laws and regulations are made, things will continue to be as they are.

My own life has been influenced by the advent of genetic screening. My brother has an inherited disorder called Narcelepsy. It is a neurological disorder that induces REM sleep even in waking periods. This disorder can be regulated by medications. It is because he has this disorder that he was denied life insurance. Or rather, was allowed to have it at astronomical premiums. This is not right. Insurance companies should not be allowed to deny coverage that could influence the welfare of my brother's family just because he has this disorder. After much arguing, my brother was allowed life insurance, not at the extreme cost as before, but still at an inflated rate.

Little Jacob was finally allowed health insurance but at an extreme cost. This is just one of the ramifications of genetic screening. On the one hand, Jacob will lead a healthy life, with just some medications along the way. On the other hand, he will always have to pay high premiums for something that was out of his control.


1. Devore, David. Genetic Screening and Ethics: an Overview. Obtained from the WWW 10/15/96:

2. Rubin, Rita. Do you have a cancer gene? New tests just coming to market can tell you. but do you want to know? U.S. News & World Report, May 13, 1996.

3. Sidransky, David. Advances in Cancer Detection. Scientific American, September 1996.

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