Genetic Screening

Dana Gietzen

Copyright 1999

Have you ever wondered what your children will look like? whether they will be boys or girls? or perhaps what your fate may be? (God willing it is of natural causes). Well, someday we may be able to answer all those questions and many more with one simple genetic test. Scientist are making new discoveries every day in the field of genetics that could possibly change our whole world as we know it. They are presently working on a project called the Human Genome Project, that will map and sequence the human genome. The basic goal of the ambitious research endeavor is to identify every gene found in the human body. There are approximately one hundred thousand genes in the human body; in a larger view, these genes are sequenced by about three billion nucleotide base pairs! Most research involved with this project focus on tests to identify genes associated with medical conditions, or at least thought to be. Once the genome sequence is known, the opportunities are endless for what scientist can discover through genetic testing about diseases and the relationship they have on the human body.

Molecular genetic testing can be dated back at least from the time when physicians were tasting urine to detect glycosuria. Today, the term molecular genetic testing refers specifically to nucleic acid analysis, usually involving DNA. In order to have successful genetic testing, scientists must unsure the highest quality of the testing process. This quality assurance includes laboratory accreditation, director certification, and proficiency testing. Surveys have been done on many research laboratories and have reported that some donít make the grade. Although some didnít have the correct requirements; a large menu of tests offered, a dedicated clinical laboratory, and board certification of the laboratory director, there was no direct evidence that serious errors were being made. For example, even if a laboratory does not follow every recommended procedure for polymerase chain reaction (PCR) containment, it does not necessarily mean that problems will occur or if they do, that such problems would go undetected and lead to false results. To set the worldís mind at ease, there are more and more groups formed every day which are dedicated to making genetic testing efficient and reliable (3).

The type of molecular genetic testing that is generating the most intense interest involves those associated with disease. This type of testing has the potential to reduce the impact of genetic diseases on the human race. According to some, there are two main classes of screening: presymptomatic, which is the detection of persons whose own health is at risk, and carrier screening, which is the detection of a healthy individual whose actual genes threaten the health or life of their future offspring. Within these two classes, several types of genetic screenings are possible: prenatal screening, newborn screening, and susceptibility screening (8).

Prenatal screening is exactly what it sounds like. Scientists test the fetus to detect various genetic disorders at early stages. This can provide parents with critical information about their pregnancies. For example, whether or not it appears normal, or if their is a gene mutation (12). Today, aside from gender, the only traits that can be identified at the earliest stages of development are about a dozen of the most serious genetic diseases. A few of these disease are gender related, so a beneficial way to reduce the risks of being susceptible to a certain disease is to choose the most advantageous gender for that child. This is very useful when trying to avoid deadly diseases that are X-linked disorders, such as, hemophilia, Duchenne muscular dystrophy, and Fragile X syndrome (6).

To determine gender, a simple rule of thumb is used: girls have two X chromosomes, while boys have one X and one Y chromosome. The mother has only Xs to offer, so the power lies with the father--specifically with his sperm, which brings either the X or a Y to the fertilization. As it so happens, the Y chromosomes have slightly more DNA than X chromosomes. So, by staining the spermís DNA with a nontoxic light- sensitive dye, scientists are able to sort sperm by gender with a high rate of success (6).

As well as prenatal screening, newborn screening is used to detect genetic disorders at an early stage. The only difference is it involves analyzing the blood and tissue samples of an early infant instead of a fetus. These diseases, if caught and treated soon enough, prevent serious health damage or death. Carrier screening is a little different than the first two tests. It is used more to set out an awareness. Carrier screening can prevent the further passing of certain disease causing genes, or it may also lead to a reduction of the effects of these genes. This test identifies those with a gene abnormality that may cause problems for themselves or for their offspring.

Conventional tests for heterozygous carriers focused on changes at the protein level. Now, new tests use recombinant DNA technology to focus directly on DNA structure. They employ a restriction enzyme and DNA probes to search for DNA patterns. These patterns distinguish reliably between family members who have a genetic disorder and those who do not. Once such a pattern has been established, it can be used to identify carriers even if the mutant protein remains a mystery (9). Susceptibility screening is used mainly to identify those who would be affected by certain toxins that may be found in their work place and cause future damage (8). With all of these tests, scientists have been able to prevent and reduce the destruction of many diseases.

There arenít many benefits to genetic screening yet, but some benefits are significant. Scientists can alert people to the fact they are carrying an abnormal gene that may cause problems for them or for their unborn children. This allows parents to take the necessary precautions when getting pregnant to reduce the risk of their child having a health problem. It also gives scientists a way for early detection of harmful diseases and allows doctors to start early treatment to reduce or completely eliminate the effects of the disease. Parents who have their children screened have a giant advantage over these genetic disorders. They are able to plan the childís life, as far as upbringing, to minimize the possibility of that child developing that disease. They can organize a diet and exercise plan, or start early medical treatment that could erase the effects of the illness and enrich their lives tremendously (1). These types of benefits have reduced the mortality rate of many diseases.

For example, twenty years ago they began a large screening program in the Jewish community (mainly those of European origin) to detect carriers of the Tay-Sachs syndrome. This recessive genetic disorder causes a painful death in children between the ages of one and five and occurs at a rate of one in every 3600 among Jews (7). Due to genetic testing the number infected with this dreadful disease has decreased ten-fold (5). Between fifty and one hundred babies used to be born with this terrible disease and today there are only ten or less (9). Genetic testing has also been beneficial in providing detection information for other diseases such as, cystic fibrosis, Huntingtonís disease, sickle cell anemia, Phetylketonuria (PKU), and many more.

Genetic testing has been helpful in preventing work-related illnesses as well. this year there was an estimated 390,000 people who contracted an occupational disease of which 100,000 of these people sadly lost their lives to (2). Genetic screening can detect those who may be in more danger or highly affected by certain chemicals found in the atmosphere of some work places. Therefore, advising that population to shy away form certain working conditions can reduce the number of work relate illnesses tremendously (5). For many, genetic screening has been a blessing from above, but still for others it is something they feel would be better left alone.

Even though genetic screening has saved many lives and has the potential to do so much more it can also be very damaging. One of the main concerns about this technique is the fact of privacy rights. People who get tested are doing it for their benefit and knowledge alone. Data should only be collected voluntarily and with informed consent. They should know exactly what their tests are going to be used for and who is going to be looking at them. Mandatory testing, testing coerced by a condition of benefits, or employment testing are all violating privacy notions (9). Employers have been known to use genetic information in an incorrect way. They use them to "weed out" certain applicants who might be sensitive to hazards in the workplace. This can be proven to be beneficial to the employee even if he doesnít see it that way. If he is more sensitive to chemicals or conditions in that particular working atmosphere it is beneficial to his health that he not get hired (5). But this is not the only way employers see fit to use genetic screening tests. They also use it to "weed out" those who may need a lot of health insurance.

As an employer sees it, he is not going to want to take the time to train a new employee if he is going to end up losing him to disability or death. He is also going to be concerned about bringing a person aboard who will cost him a lot of money for medical treatment due to a contracted work-related disease. We, as the public, on the other hand see this as discrimination for having the wrong genes that may or may not cause a disease (5). for example, a study of support groups for genetic disorders revealed that nearly one fourth of the members had experienced this type of discrimination (11). Discrimination is not only happening in the workplace, it is also happening a great deal with insurance companies.

Insurance companies make money only so long as people pay more to buy health insurance than it costs the insurance company when these people feel ill enough to consult a physician. Basically, the only way they make a profit is to sill most of their insurance to those who wonít get sick. this way they use barely any money to cover those who are actually sick, making the profit gain much in their favor. With a persons genetic information, a company con predetermine whether or not they are likely do develop a medical condition (5). Thus, by raising their premiums immensely or completely denying them coverage form their company a person can be discriminated again for their gene make-up (4). How are we supposed to keep our genetic information from getting into the hands of those who could cause us more harm than help? In over thirty states, laws have been passed to prohibit this kind of use for genetic screening and more and more genetic discrimination bills are on the rise but can this really protect us (4)?

A more dangerous outcome of genetic screening does not deal with the actual results, but with what it may imply people to do. Genetic screening has begun to reduce pregnancy from a miracle of life to a chopping spree for merchandise. Within a decade or two it may be possible to screen children, even before conception, for an enormous range of characteristics such as, how tall they will be, what body type they will have, their hair and eye color, what sort of illnesses they will be naturally resistant to, and some scientists are going as far as the actual IQ or personality type. Parents may start going beyond the duty of weeding out undesirable traits and start actually inserting genes they want (6). Hopefully that is in a future we will never see. Unfortunately, at the present time there are problems that are in a bracket of their own. Today, if the fetus has a genetic disorder or a gene mutation that could cause problems or even become fatal, for most situations, it is aborted. Scientists have identified many diseases, without cures, and parents find it difficult to believe they would be doing the right thing by bringing a child into this would that may already be infected or could possibly develop a non-treatable disease (8). Some people are even starting to worry that this is giving the impression that if someone is abnormal or defected then he should be eliminated or thrown out like trash. this could cause a wave of selective breeding. Parents feeling a need to have their children genetically perfect in order to survive and be accepted into the world (4). People need to realize that every person is going to have at least one abnormality whether it is major or minor and if we didnít have genetic defects, then what would be the purpose of spending all this time and money towards techniques to try and treat them (10).

When it comes to my opinion on this matter I would have to say that it goes both ways, but a little more one way than the other. I feel that when put to a good use, genetic screening can work wonders for the human race. It can give an early diagnosis of a few threatening diseases that can be cured or controlled with treatment. It allows the patient to understand what he is up against at an early stage and gives him the time to make adjustments to his lifestyle and diminish or eliminate the effects of the disease. I think it is also beneficial in the fact that it places awareness to those who carry a gene that could possibly cause harm to themselves further along in their life or cause extreme damage to their future children. It enables them to take the necessary precautions to bear healthy children and reduce the risk of developing the genetic disorder themselves. On the other hand, I feel that there are many more issues against genetic screening than there are for it.

A big issue for me is the discrimination factor. I feel that it is wrong for companies to take something that was created for good use and turn it into something bad. Discriminating people for their genetic test results is just as bad as doing it because the color of their skin. An even bigger issue is the fact that genetic screening tests are based on predictions. Relatively few genetic diseases are deterministic. Most tests cannot tell us if a genetic mutation will become manifest; if it does, when in life this will occur; or how severe the condition will be. Even with that, many of the genetic conditions detected can be treated or controlled. There are so many people who experience discrimination because the color of their skin, or the shape of their body is too big, or they come form the wrong part of town. Do we really need to bring another issue of discrimination to the table, especially one that goes down to a persons genes? Also, if employers were to maintain the use of such tests as a "weeding tool" Iím afraid that it would cause people to shy away form having genetic test done all together. This could prove to be much more harmful to those needing the test than to those running the companies.

I also disagree with genetic screening when it comes to selective breeding. I feel that it is morally wrong for parents to abort their babies just because it has a genetic defect. They may try and justify their actions by thinking it is saving them and their child a lot of pain, but I for one think it has more to do with the fact that their family wonít fit into societies category of "normal." It seems in todayís world everyone is striving to have the best of everything. The biggest house, the best car, and now the most genetically perfect children. If everyone were to start judging which children had the right to be born according to their genetic make-up, we may clear out the whole human race. It is time for people to realize that there is no such thing as a perfect person. We are all going to have our faults.

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