What is Genetic Screening?
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Assessment of an individual's genetic makeup to detect inheritable defects that may be transmitted to offspring or genetic predisposition
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to certain illnesses. U.S. Congress Office of Technology Assessment (OTA) differentiates this from Genetic testing where the purpose is to identify the genetic make-up of a patient whose inherited susceptibilty to certain ailments are already recognised.
Background Information: •
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The human genome* contains 23 pairs of chromosomes, one copy inherited from each parent. We could think of human DNA as an encyclopaedia. Testing a specific gene inolves pulling out the right volume (chromosome) and looking for spelling errors on a particular page. A large proportion of human health has a genetic basis. Inherited genetic diseases are caused by abnormal forms of a single or a group of genes that are passed on from one generation to the next. Some diseases are caused by a single mutation, while others involve a complex interplay among many genes and environmental factors. For instance, a woman who inherits mutations in either of two genes (BRCA 1 in chromosome 17 and BRCA 2 on chromosome 13) is about five times as likely to develop breast cancer as a woman who does not have such a mutation.
*The mapping of the human genome was completed in 2003 at the cost of $2.7 billion.
Ponder: •
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The human genome is exquisitely complex, so geneticists often find in patients problems they were not initially looking for. Should they alert their patients about these additional findings? What if these diseases have no cures yet? Should parents tell their children what might await them as adults? We have numerous new diagnostic and curative methods for age-old diseases and an accompanying plethora of questions about how to use them wisely - Are we being outpaced by technology?
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Case Study 1: 1) Fragile X syndrome
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Most widespread single- gene cause of autism,
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Individuals with FXS are known to have learning disabilities due to a lower Intellectual Quotient (IQ) level, facing challenges mostly in working and short- term memories, and even mathematics. They also face social anxiety and autism.
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Prenatal testing is possible to find out if fetus has FXS.
Implications: - Ethical issues like abortion might rise in screening for FXS. What if parents, upon knowing their children have FXS, choose to abort them? Should such screening be prohibited? -
There is a 50% chance that FXS may be passed on to the affected individuals’ children. Allowing genetic screening may prevent unnecessary discrimination if the child truly does not carry the affected gene.
Case Study 2: 2) Criminology: Natured or Nurtured?
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Genetic research suggests the possibility that individuals possessing the XYY chromosome may have a higher chance of being a criminal than expected.
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Survey results reveals that the XYY chromosome appears more than 510 times in prison inmates than the expected numbers based on chance alone.
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If theory is established, future individuals with the XYY chromosome may be discriminated.
Implications: - Might affect criminal responsibility argument in the future. Should the individual be allowed to present his genetic make-up as a form of defense against his sentence? Is it justifiable to ask for a lighter sentence based on the gene? -
Nature vs. Nurture controversy (criminal causation) is the cause of crime by humans by his nature, or is it affected by other factors?
Negative Implications of Genetic Screening: G ENETIC D ISCRIMINATION Genetic discrimination occurs when employers or insurance companies treat people differently due to gene mutations that might cause or increase the risk of inherited disorders. People who undergo genetic testing may be at risk of genetic discrimination. The results of a genetic test are normally included in a person’s medical records. When a person applies for life, disability, or health insurance, the insurance company may ask to look at these records before making a decision about coverage. An employer may also have the right to look at an employee’s medical records. As a result, genetic test results could affect a person’s insurance coverage or employment. People making decisions about genetic testing should therefore be aware that their results are not kept private. Fear of discrimination is a common concern among people considering genetic testing. Several laws at the federal and state levels help protect people against genetic discrimination; however, genetic testing is a fastgrowing field and these laws don’t cover every situation.
D ISTRESS
WITHIN FAMILY
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Since genetic alterations generally need to be identified in a family member who has already developed cancer, this can lead to distress and fray family relations; For example if there are no surviving family members who are able to undergo diagnostic genetic testing, or if an individual is reluctant to undergo testing he/she may be subject to pressure from other family members. A positive genetic test can also lead to an increased level of anxiety and individuals may feel guilty for having potentially passed a gene alteration on to their children. There may also be issues for individuals wishing to obtain health and life insurance. Receiving a negative genetic test can also affect family relations, with many individuals feeling ‘survivor guilt’; For example if they have a brother or sister who has been shown to carry that gene alteration, they may feel guilty at having escaped the increased cancer risk, while their sibling is still at risk.
Positive impacts of Genetic Screening: I NCREASED
QUALITY OF LIFE
Individuals who are found not to carry a harmful gene alteration, which is known to run in their family, may feel that they are less anxious and have a better quality of life; they may also benefit from the knowledge that they have not passed a gene alteration on to their children. Also, because such individuals do not require the same regular checkups as do people who carry the gene, resources can be targeted to benefit those people who do have a higher risk of developing cancer.
A BILITY TO
BETTER PLAN FO R THE FUTURE
DNA testing allows doctors and families to plan for the future onset of potential diseases, both financially and mentally. This might even discourage carriers of incurable conditions from propagating debilitating genes to children.
Check out these videos:
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Controversies: https://www.youtube.com/watch?v=W6sDwEOfbjU
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New ways to test genes: https://www.youtube.com/watch?
v=fzveyifKtoQ
3. TED talk on “genomic revolution” http://www.ted.com/talks/richard_resnick_welcome_to_the_genomic_rev olution.html
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