Genetic testing refers to the testing of segments of a population, as part of an organised program, for the purpose of detecting inherited disorders.
Genetic testing may be carried out for various of reasons, for example, people who are at high risk of inheriting a faulty gene, based on their family history of occurrence of inherited disorder. Genetic testing can be performed on a sample of blood, hair, skin, amniotic fluid or other tissue.
Types of genetic testing:
There are many types of genetic testing, these are
Newborn screening: is used just after birth to identify genetic disorders that can be treated early In life
Diagnostic testing: used to identify or rule out a specific genetic or chromosomal condition
Carrier testing: used to identify people who carry one copy of a gene mutation that when present in two copies causes a genetic disorder
Prenatal testing: used to detect changes in a foetus’ genes or chromosomes before birth
Preimplantation testing: specialised technique that can reduce the risk of having a child with a particular genetic or chromosomal disorder
Predictive and pre symptomatic testing: used to detect gene mutations associated with disorders that appear after birth, often later in life
Forensic testing: uses DNA sequences to identify an individual for legal purposes
Disadvantages of genetic testing:
If the genetic cause of a disease is identified in a patient it doesn’t guarantee that there is a cure for that disease.
Advantages of genetic testing:
through genetic testing we may be able to screen populations for diseases in order to better diagnose, treat and prevent disease.
Reducing the incidence of disease has major impacts on and is of great importance to:
Families: When a child is born with a particular disease, there may be no apparent family history. With simple genetic testing for carrier status of the parents, the birth of a child with disease could have been prevented.
Health resources: The birth of a child with a genetic disorder adds stress to health systems and resources. Carrier screening programs could act as important components of the medical system in preventing disease through offering people
informed reproductive choices.
A positive result can direct a person toward available prevention, monitoring, and treatment options. Some test results can also help people make decisions about having children.
Biological concepts of genetic testing:
-sexual reproduction
One of the parents carry a disorder or a faulty gene they didn’t know about and they are trying to identify the disorder
Ethical, social and legal implications associated with genetic testing: As carrier screening would involve the screening of a possibly asymptomatic population, it inevitably raises a number of ethical issues in terms of consent, privacy and education, which need to be considered. It is important that all people involved are appropriately educated.
Prenatal genetic screening can inform parents of the health status of their unborn child. In the case of a prenatal diagnosis of disease, parents are able to assess their options and make decisions accordingly.
Communicating Test Results It is critical that genetic test results are discussed with patients in an understandable manner. As many genetic tests will not provide simple positive/negative results, but potentially inconclusive results or risk estimates, it is important that patients understand the extent of the information actually provided from a genetic test.
Direct-to-consumer Tests A number of companies market genetic tests directly to consumers without requiring physician involvement. Patients should be cautious when considering direct-to-consumer genetic testing and encouraged to discuss this option with their healthcare professional.
Duty to Disclose The results of a genetic test may have implications for a patient’s family members. However, health care providers have an obligation to the person being tested not to inform other family members without the permission of the person tested, except in extreme circumstances. If a health professional believes family members may be at risk, the patient may be encouraged to discuss test results with other family members.
The American Society of Human Genetics suggests that disclosure to at-risk individuals is permissible when the following criteria are met:
Attempts to encourage disclosure on the part of the patient have failed
Harm is highly likely, serious, imminent, and foreseeable
At-risk relatives are identifiable
Disease is preventable, or medically accepted standards for treatment or screening are available
The harm from failing to disclose outweighs the harm from disclosure
Genetic Discrimination When considering genetic testing, a major concern often raised is the potential of discrimination based on genetic information. Since genetic test results are typically included in a patient’s medical record, patients should be aware that the results may be accessible to others. As a result, genetic test results could affect a person’s insurance coverage or employment.
Informed Consent To help ensure that patients understand the risks and benefits of health care choices, informed consent is an important part of the medical decision-making process. For patients considering genetic testing, the following items should be carefully discussed and understood before consent is obtained:
Testing is voluntary
Risks, limitations, and benefits of testing or not testing
Alternatives to genetic testing
Details of the testing process (for example, what type of sample is required, accuracy of test, turn around time, etc.)
Privacy/confidentiality of test results
Potential consequences related to results including
Impact on health
Possible emotional and psychological reactions
Treatment/prevention options
Ramifications for family
Privacy Genetic information has enormous implications to an individual and his or her family. The privacy of that information is a major concern to patients: in particular, who should have or needs access to that information.
Psychosocial Impact Every individual will respond differently to news of his or her genetic test results whether negative or positive. As there is no right or wrong response, health professionals should refrain from judgment and help the patient understand what the test results mean with respect to their own health, available interventions or follow-up, and risks to their family.
Reproductive Issues Genetic information is routinely used to inform reproductive decisions and medical care. Risk factors for genetic conditions for which preconception or prenatal genetic testing may be considered include advanced maternal age, family history, multiple miscarriages, or drug and alcohol exposure. As these procedures carry risks and benefits, parents should carefully consider and discuss these options with a physician or genetic counselor.
Societal Values Genetic information can raise questions about personal responsibility, personal choice versus genetic determinism/fate, and concepts of health and disease. Personal factors, family values, and community and cultural beliefs will influence responses to these issues. While genetic information may influence one individual to change his or her lifestyle or behavior in order to reduce risk or disease severity, others may choose to respond differently.
Test Utility The useful application of genetic tests will depend on the correct interpretation of test results and their utility in guiding medical care and treatment. However, for some genetic conditions, the utility of genetic test results may be limited if no treatment is available or if the results are inconclusive. These issues should be discussed with patients or parents of patients when a genetic test is being considered.
Test Validity Several issues regarding test validity should be considered prior to ordering a genetic test. The analytical and clinical validity of a test are generally measured as test specificity, sensitivity, and predictive value. This information should be shared with the patient as they consider whether or not testing is appropriate for them.
Scientific investigation: Direct-to-consumer genetic testing
A patient aged 28 years presents to her general practitioner (GP) with the results of her genetic tests, which she had ordered online to check her risk of breast cancer after reading about Angelina Jolie.
Direct-to-consumer genetic tests are tests that are conducted by laboratories without requiring a referral from a health professional. These tests may cover health and non-health matters, such as paternity and ancestry. The tests are often promoted on websites by laboratories that are overseas, and, therefore, not subject to Australian regulations, such as the Therapeutic Goods Administration.
A publication produced by the National Health and Medical Research Council (NHMRC), Discussing Direct-to-Consumer Genetic DNA Testing with Patients – A Short Guide for Health Professionals, warns that health professionals should carefully consider the implications of discussing a direct-to-consumer genetic test result with a patient, noting that a patient may be placed at harm should the health professional attempt to provide therapeutic advice on the basis of a test of unknown analytical and clinical validity.1
Conclusion: genetic testing revealed many things that can happen when you have it done. It revealed many ways which it can be tested and what it can be tested for and on, it had shown that in many ways it can help people in good ways and many ways in which it can be bad.