Genetic testing: Pros and Cons
Recent decades have witnessed the fast-paced development of genetic testing methods, particularly in prenatal studies. These techniques are powerful tools to examine the changes in the whole content of DNA that may cause disease. The result of a genetic test can range from the confirmed or refused possibility for a genetic condition to support a person’s risk of developing or passing on a genetic disorder. Currently, over 1,000 genetic tests are in use, and more will design for the near future.
Several methods can be applied for genetic testing, such as; molecular genetic tests, chromosomal genetic tests, and biochemical genetic tests.
• Molecular genetic tests are applied to identify possible variations or mutations in DNA sequence from a single gene to short length repeats, leading to genetic disease status. These methods are performed as newborn screening to confirm rare or recessive genetic disorders like phenylketonuria and cystic fibrosis. Meanwhile, they are also used as predictive testing to detect more common and complex conditions, usually with adult-onset symptoms such as most cancer, cardiovascular diseases, and diabetes.
• Chromosomal genetic tests detect the possible extensive genetic changes, such as a missing or an extra copy of a chromosome through the entire length of chromosomes for a likely abnormality condition. These tests are widely used as prenatal screening and diagnostic in two ways, namely, invasive and non-invasive testing depend on the state.
• Biochemical genetic tests examine both quantity and activity levels of enzymes or proteins to see if any abnormality exists. The altered amounts of enzymes or proteins caused by errors in the metabolism system lead to congenital disabilities in children, such as Tay Sachs disease and phenylketonuria.
Since genetic testing has several benefits besides its limitations and risks, the decision to take the test is entirely personal and voluntary. In this condition, genetic consulting can provide comprehensive information about the positive and negative features of the test and debating the social and emotional aspects of testing with patients and their families.
Risks and Limitations
The physical risks associated with genetic testing mostly depend on the sampling procedure. Particularly for those tests that require only a blood sample or buccal smear, the risk is noticeably lower than the condition in which prenatal testing carries a real risk of losing the pregnancy. For instance, in QF-PCR as an invasive technique, the sampling procedure is taken through the amniotic fluid, or chronic villus sampling (CVS) extractions that might trigger the fetus life. genetic testing also involves the emotional, social, or financial consequences that make the decisions more complicated. Mothers may somehow feel depressed and anxious when the result their test informs the possibility of chromosomal defects in the fetus. Furthermore, in some cases, genetic testing can create massive pressure on a family as the results show the potential risk of disease in family members as well. Regarding the community, the social complication of genetic testing is issues like discrimination, privacy and confidentiality law, informed consent, access to genetic information by employers and insurance companies, and appropriate use of testing for prenatal or pre-symptomatic diagnosis. Finally, the cost of genetic testing is relatively considerable in complex cases and the condition that one test is not sufficient or even if some family members must be involved in the trial to achieve a meaningful result. Since most countries offer the analysis in private sectors, they do not cover the cost of genetic testing making families in the pressure to afford.
One of the main limitations of genetic testing is providing restricted-scientific evidence to evaluate the outcomes, especially in predictive ones like prenatal diagnosis testing. The limited information results from several factors, including test complexity, rapid development pace, and its socio-economic impacts. For predictive genetic tests, the most significant challenge might be to achieve well-developed equipment and randomized trial controls, especially in regions of the world that face with considerably limited access to next-generation sequencing amenities. Furthermore, lacking enough data on efficiency affects the evaluation of cost-effectiveness. In this condition, the geneticist can’t determine how the symptoms or disorder will manifest or how loads of abnormality will be, or the growing pace of disease will change over time. That is why the non- invasive prenatal testing (NIPT) is not the stand-alone technique in the majority countries of the world. The test is a relatively expensive method and provides inconclusive evidence in terms of false-positive required further examination by invasive tests. Another major limitation is the absence of treatment and management strategies for those genetic disorders newly diagnosed. Considering the application of gene therapy in a clinical trial of the genetic disease in previous decades, it faced numerous obstacles and many failures. However, it has made massive progress in personalized medicine and is taking its path to the clinic and the market share.
In summary, rapid development of genetic tests has made the assessment of their performance crucial for clinical and public health practice. A genetics professional can explain in detail the benefits, risks, and limitations of a particular test because any person considering genetic testing must understand and weighs these factors before making a decision.
