MRC National Institute for Medical Research, London

To screen, or not to screen, that is the question. Cystic fibrosis, Huntington’s, sickle cell anaemia, Tay-Sachs and Canavan disease are just a few of the many diseases that can be screened for thanks to revolutionary advances in science. But what are the limitations of genetic screening? Could we test for factors other than genetic diseases? Cue the opening scene of Andrew Niccol’s 1997 sci-fi film ‘GATTACA’ where the birth of the protagonist is quickly followed by a blood test which divulges detailed genetic information on the newborn, including probabilities of having certain disorders and health conditions. Genetic screening has become a somewhat controversial topic in society, but do we really have anything to fear from it? Many are the under the impression that genetic screening is a fairly recent discovery. But the real history of genetic testing really began sometime between 1879 and 1882 when Walther Flemming discovered chromosomes. Fast forward some 100 years and all newborns were being tested for PKU (phenylketonuria) a disease in which brain function deteriorates due to a build up of phenylalanine in the blood. And if the child did have PKU, a strict diet would be enforced which would preserve brain function[1]. Another positive outcome of genetic screening is seen in the Jewish community where a group called 'Dor Yeshorim', based in Brooklyn, New York, completely transformed Tay-Sachs testing and took it to a completely new level by screening young people for this disease to determine if they were likely to produce offspring with two copies of the Tay-Sachs gene. Some may call it selective breeding, but the disease has completely disappeared from this particular population[2]. However many people fear genetic screening. It seems that increasingly the public have concerns about insurance companies using genetic information to decide whether to provide cover for individuals. Could there be such a thing as genetic discrimination? And could this fear deter people from genetic screening out of panic that it will affect their ability to acquire health or life insurance[3]. At the moment, companies cannot demand screening and it is not mandatory for policies worth less than £100,000 or for new mortgages. Nonetheless companies are allowed to ask for the results of tests if an individual has already had one. Although genetic information is confidential, people still have this fear[4].

On the other hand, there are many advantages of genetic screening; one of them simply being the knowledge gained from it. An individual can find out of they are at risk of inheriting a particular disease or if they are a carrier of a disease. If the diagnosis is certain, individuals can prepare for it by gaining more knowledge of that disease or through genetic counselling. Carrier screening is an advantage to couples who have a family history of genetic disorders and want to have children. Through this they can weigh up the risks and chances of their child having the disease based on their genes. Furthermore if a genetic abnormality is found patients can seek early treatment that may allow them to live a longer and fulfilling life. Also if a cancer-causing gene is found, individuals can alter their lifestyle in order to avoid the expression of that particular gene[5].

However many people fear this idea of knowing too much about themselves. Imagine if you get screened and you find out that you will develop an incurable disease like Huntington’s that will lead to your inevitable death, how would you feel? There are also many ethical issues surrounding genetic screening, some may view it as a step towards a world of ‘designer’ babies or a world where eugenics is socially acceptable. Many religious groups oppose and fear genetic screening as it is considered to be interfering with God’s creation. Roman Catholics in particular oppose it because foetal genetic screening may lead to people choosing to terminate a pregnancy if the child is found to have a genetic disease, and this is incompatible with their belief in the sanctity of life. The main fear from genetic screening is the possibility that ‘perfect genes’ may become an ideal, so that people who are not genetically perfect might be treated as inferior[6] [7].

Throughout history new and controversial scientific discoveries have provoked uproar from society because of fear of the unknown. When Galileo argued for the theory of Copernicus, that the Earth is not the centre of the cosmos, he was persecuted for the crime of heresy. But without new ideas there would be no scientific progress or progress in our lives and lifestyles. Our fear of genetic screening may be because its a topic that pushes the boundaries of human ethics well beyond our comfort zone. But in the beginning there is always fear and uncertainty; as we gain knowledge and experience society will slowly start to accept genetic screening just as society did with the Copernican system. Genetic screening has numerous exciting prospects but they come with a few difficulties. So do we have anything to fear from genetic screening? At this moment in time many would say no, but who knows what the future may hold.

References

1. Scienceprogress.org/a-brief-history-of-genetic-testing
2. Ezinearticles.com/the-history-of-genetic-testing
3. Bunting, J. (1995) Genetics: Tomorrow’s World
4. brighthub.com/science/genetics/articles
5. Beatty, R. (2001) Genetics: Science Fact File
6. bbc.news.co.uk/health
7. Hooper, T. (1993)Genetics: Breakthrough

The cruelty of an inherited genetic disease lies in the knowledge that they are unpreventable, incurable and often fatal. However, this may no longer be wholly true. Tremendous advances in the study of genes have meant that a genetic defect, which has plagued a family for generations, could finally be eliminated with the use of genetic screening. But genetic screening, defined as a 'systematic search for persons with a specific genotype', has come under intense criticism and its immense potential to ultimately give an insight into our genetically determined futures strike fear in many.[1]

Genetic screening concerns information at the highest level of sensitivity and it is the overwhelmingly personal nature of our individual genetic code that is central to our fears. Our unique genetic sequence gives each of us the exclusive rights to our appearance, behaviour and even personality. If this code is unravelled, the wealth of information unlocked could have far-reaching implications; particularly if they reveal untreatable conditions which have not previously expressed themselves. The question arises as to the impact of such insight into our potential fates and who, other than the individual screened, would have the right to access these results. Genetic screening could potentially be a legal minefield as the issues of confidentiality arise. This may become apparent when a result for an individual, who has given their consent to be screened, creates serious implications for family members, who have not given their consent.

A fundamental fear is the way the information from genetic screening will be employed. The results of genetic screening have been identified as a potential cause of discrimination and stigmatism on the grounds that some may be declared to have a genetic predisposition which makes them more likely to succumb to illness or disease. Employers with access to their employees’ genetic profile could become prejudiced against employees with a genetic trait which makes them less suitable to an occupational workplace.[2] Thus genetic results could be used to exclude and reduce opportunities.

Concerns also stem from the possibility that genetic screening will be abused for non-medical purposes. Suggestions that genetic screening will revive the Eugenics movement inevitably strike fear in people as only embryos classified as 'normal' may be allowed to develop. Additionally, the prospect that parents have the ability to select offspring with ‘desirable’ superficial characteristics may only serve to exacerbate issues of inequality and discrimination.

Despite our fears, genetic screening has already been used successfully in primary health care. Since 1973 it has been standard procedure to screen all newborn babies in the UK for phenylketonuria (PKU) and pregnant women have been routinely tested for their rhesus blood group since the 1960s.[2] The knowledge gained from these genetic screening programmes has allowed babies at risk of rhesus disease to be treated immediately with an injection of antibodies, preventing the development of blindness, learning difficulties and deafness whilst babies screened positive for PKU can be put on a diet low in phenylalanine, preventing the development of mental retardation in later life.[3][4] It is evident from the current uses of genetic screening that prior knowledge of inherited diseases enables steps to be taken to prevent severe symptoms from developing.

Genetic screening employed in fertility science is arguably one of the most promising examples of how genetics have made a profound impact to the lives of families. The advent of Pre-implantation genetic diagnosis (PGD), or embryo screening, in the 1990s gave rise to new hope for families affected by a genetic abnormality. Diseases such as Cystic Fibrosis and Myotonic Dystrophy are severe, debilitating illnesses which have the capacity to reduce the sufferer’s quality of life and life expectancy. A child with a genetic disease can also place a heavy emotional burden on parents and impact adversely on family life. Genetic screening enables ‘healthy’ embryos produced by IVF to be distinguished from those carrying a genetic defect. [5] As only embryos showing a normal chromosome pattern are implanted, the couple’s chance of having a baby without a genetic disease are drastically increased.

Genetic screening has enabled prospective parents to make better informed choices. Once the risk of having a genetically abnormal child is established, parents will have the knowledge needed to consider the options available. For example, PGD was first introduced to determine the sex of an embryo at risk of a sex-linked chromosomal disease such as Duchenne muscular dystrophy (DMD). DMD is a recessive X-linked disease that mainly affects males. If there is a family history of DMD, parents may choose to have a female embryo rather than a male to be implanted, reducing the likelihood of having a baby with DMD. Furthermore, PGD allows parents to ensure that their children will be unaffected by a genetic disease without the need for prenatal testing, which would then involve the difficult decision of termination.[6]

Genetics is a constantly evolving field of science and the prospect of using genetic screening to identify individuals with a genetic predisposition of developing diseases such as Coronary Heart Disease (CHD) and Cancer is becoming increasingly probable. However, these diseases are multifactorial and it is known that environmental factors can exacerbate their onset and development. Determining an individuals’ genetic susceptibility would allow them to receive advice on how to minimise their risk by making diet and lifestyle changes before the diseases develop to a greater extent.

In conclusion, the fear of genetic screening has arisen because of its potential to induce extensive implications not only for the individual screened but for their families. However, the benefit to be gained from genetic screening is overwhelming. The ability to reduce the incidence of genetic diseases prevents the suffering of many, whilst the knowledge gained from genetic screening can assist in reducing the development of degenerative diseases such as CHD. Though the use of genetic screening will not completely eliminate genetic diseases as genes continually change and mutate, genetic screening is one of the defining advances in the 20th century which will revolutionise the treatment and diagnosis of disease.

References

1. http://www.ndsu.edu/pubweb/~mcclean/plsc431/students/kjono.html
2. http://www.nuffieldbioethics.org/genetic-screening
3. http://www.nhs.uk/Conditions/Rhesus-disease/Pages/Symptoms.aspx
4. http://www.marchofdimes.com/baby/birthdefects_pku.html
5. http://www.fertilitycenter-uconn.org/programs_preimplantation_faqs.htm
6. http://www.nature.com/scitable/topicpage/embryo-screening-and-the-ethics-of- 60561

Concerns over genetic screening - which essentially involves testing people for conditions which they have not encountered before – perhaps reflect a human tendency towards ambivalence about progress generally; if any given advance is in some sense 'revolutionary', it will carry risks as well as beneficial possibilities. As a complex area of 'progress', genetic screening entails a wide variety of areas for consideration, including what it aims to achieve, how it is justified, various moral and ethical issues, and the potential risks and benefits of further development.

First, the diagnostic aims of genetic screening are varied. Some tests allow early treatment of conditions in newborns, such as Phenylketonuria and Congenital hypothyroidism. Others simply give warning of future problems. Carrier Identification includes the tests that are used for couples wanting to have children, who have a family history of recessive disorders, (such as Cystic Fibrosis, Tay-Sachs disease, and sickle-cell anaemia). Similarly, but more controversially, Prenatal Diagnosis tests the foetus for changes in genes or chromosomes before birth. (2) This is used for couples that have an increased risk of having a baby with a chromosomal disorder such as Down syndrome. (3) Screening begins with the parents' medical history; if both possess the gene for a disorder, they can choose to abort the foetus. The government is considering increasing the screening programmes for pregnant woman to reduce the number of babies born with inherited diseases, arguing that the expense is justified since most mothers terminate pregnancies after being tested positive. (4) Such an application of science and 'cost-benefit analysis' to the often romanticised and religiously respected process of pregnancy and childbirth is controversial for many.

Other commentators fear that genetic disorder screening may also eventually be used to select 'designer babies' and screen out offspring with less serious abnormalities. (5) Legally, parents can decide to abort their foetus if they have a disease such as Down Syndrome. Ethically, however, this is dubious since life expectancy with Down Syndrome can reach sixty. The ethical debate is hampered by a lack of consensus over what constitutes a relevant disease in this context. For example, if the symptoms of a disease only strike at the age of 45, should this be accepted as grounds for an abortion? This raises a further question: who should decide whether testing should be done? (6)

Various cases can be made for compulsory screening. Arguably, the state has an obligation to create awareness among individuals about their own health. Screening is also relatively inexpensive and has the potential to control diseases at a population level and save lives. For example, a study by the WHO in 2002 estimated that there was a 35% reduction in mortality among women who participated in screening programmes. (11) It would serve an educational purpose; cousins who plan to marry, for example, may receive counselling to assess their children's risk of inheriting a life-threatening disorder. This assessment allows parents to be aware of the problem instead of realizing after they have had their first child. (4) It is difficult to deny that screening allows for early diagnosis, prevention and care treatment. A simple cure can enable a child to have a normal life; for example phenylketonuria is a disorder where babies are unable to break down the amino acid phenylalanine found in food and which can cause severe brain damage – but preventable by providing a low phenylalanine diet early. (11)

But the arguments against screening – especially compulsory screening – are equally compelling. These do not primarily rest on the possibility that discovering genetic flaws may lead to discrimination with regard to employment or insurance. The Genetic Information Non-discrimination Act (passed in 2008) prevents companies from discriminating against a person based on genetic disposition. (7) Thus; privacy is recognised legally as crucial to the process of screening. Rather, the value to the individual of gaining the information is often questionable. Patients will react differently to screening results; if a doctor tells a patient that they have the gene for a disease, they may misinterpret this as having the actual disease. This risks 'turning healthy people into patients'. (9) Since testing positive for diseases such as Huntington's is a definite indication that the disease will eventually develop, how would this knowledge improve the patients’ lives in the meantime? Such knowledge may even be socially divisive; if those with ‘healthy’ genes are able to avoid mating with those with recessive genes, it is possible that a genetic underclass may appear. (8) Finally, genetic profiles remain hard to interpret and there is still a clear risk that results provided will be inaccurate. (5)

Simply fearing genetic screening on these grounds, however, is not a reasonable way forwards; this will only create more anxieties. Science is forever growing and generating new concepts; at any one time its ideas may not be accepted by some people but may be embraced by others. Screening could benefit millions of people but it is really important they understand all that it involves before taking this decision. In short, we should not fear Genetic Screening specifically because we still know so little about it – but we shouldn’t be completely oblivious either. We as humans should not be in fear of technology; we should continue trying to understand it.

"Our society went into the age of nuclear energy blindly and we went into the age of DDT and other pesticides blindly. But we cannot afford to go into the age of genetics blindly. Instead we must move into this exciting new era with awareness that gene therapy can be used for evil as well as for good. As we reap the benefits of this technology, we must remember its pitfalls and remain vigilant." (12)

References

1. www.macminn.org/Genetic%20Testing1.ppt
2. http://www.lbl.gov/Education/ELSI/genetic-testing.html
3. http://www.encyclopedia.com/topic/genetic_screening.aspx The Columbia Encyclopaedia, Sixth Edition
4. http://www.guardian.co.uk/science/2003/sep/03/genetics.politics?INTCMP=SRCH
5. http://www.telegraph.co.uk/health/healthnews/8189668/Babies-DNA-profiled-in-the-womb.html
6. http://www.woodrow.org/teachers/bi/1992/gen_screen1.html
7. http://www.lbl.gov/Education/ELSI/genetic-testing.html
8. http://www.guardian.co.uk/science/2003/sep/03/genetics.politics?INTCMP=SRCH
9. http://www.newscientist.com/article/mg18624973.500-genetic-screening-can-be-fearfree.html
10. Biology Textbook Fourth edition Solomen, Berg,Martin,Villee
11. http://www.bma.org.uk/images/ScreeningBriefing2_tcm41-20993.pdf
12. www.macminn.org/Genetic%20Testing1.ppt W. French Anderson, Scientific American, 1995