Everything You Need to Know About Genetic Testing
According to the Organization for Rare Diseases in India (ORDI), 1 in 20 Indians is affected by a rare disorder. More than 7,000 rare diseases are known and reported worldwide; of these, approximately 80 percent are known to have a genetic predisposition. Some of these “common” rare diseases that we have heard of are inherited cancers (eg breast, ovarian and colorectal, etc.), hemoglobinopathies (hemophilia, thalassemia and sickle cell anemia, etc.), autoimmune deficiencies and lysosome storage disorders, among others, says Dr. Aparna Dhar, department head: Medical Genetics and Genetic Counseling, CŌRE Diagnostics.
“In 2020, the world has undergone massive changes. It has made us introspect and re-evaluate our lives. We begin to take care of our well-being by addressing the problems associated with mental health and physical health. We have consciously tried to achieve lifestyle changes that have been combined with partnering with healthcare / diagnostic providers to bring us a more personalized approach. A key way to do this is by understanding whether they have a genetic predisposition to an inherited disorder, “he adds.
A global study conducted by the Mayo Clinic, USA, stated that 1 in 10 people who underwent predictive genetic testing, learned that they had an inherited risk of a health condition and could actually benefit preventive care. While no genetic test can accurately predict the exact date and time a disease may develop, it will definitely be able to tell whether a person is at greater risk than the general population’s risk.
However, Dr. Dhar says there is definitely a lack of awareness about these genetic disorders, a misconception about genetic diseases and testing, a taboo when talking about a possible family disorder, and cost challenges.
Here, he addresses some of these:
What is a genetic test?
Genetic testing is a type of medical test that identifies changes in chromosomes, genes, or proteins. The results of a genetic test can confirm or rule out a possible genetic condition or help determine the likelihood that a person will develop or transmit a genetic disorder. More than 1,000 genetic tests are currently in use and more are being developed. Genetic testing is done on a sample of blood, hair, skin, amniotic fluid (the fluid that surrounds the fetus during pregnancy), or other tissue.
For example, a procedure called a buccal swab uses a small brush or cotton swab to collect a sample of cells from the inner surface of the cheek. The sample is sent to a laboratory where technicians look for specific changes in chromosomes, DNA, or proteins, depending on the suspected disorder. The laboratory reports the test results in writing to the individual’s physician or genetic counselor, or directly to the patient if requested.
How should one prepare for genetic testing?
Genetic testing can provide important information that can save lives. Interpretation of the results is essential. It can be difficult for a doctor to understand the result if he or she does not have specialized training in genetics. That is why there are genetic counselors. They are trained in both medical genetics and counseling and work closely with your doctor to provide both clinical and emotional advice. They are available to guide you, to make sure you are a good candidate for the test, and to help interpret the results. While for some, they may think better of it and not recommend genetic testing as it is not for everyone. While there is a perceived stigma of being the result of some disease or bad gene, a counselor will help you understand what the results mean for you and your family.
Genetic testing is the need of the moment. (Source: Getty Images / Thinkstock)
What useful information can genetic testing provide?
* Genetic testing can provide clarity on results, guide therapy selection and monitoring, and enable disease risk profiling
* Family health history tells you which diseases are inherited
* Identify risks due to shared genes.
* Better understand what lifestyle and environmental factors you share with your family
* Understand how healthy lifestyle choices can reduce your risk of developing the disease.
Genetic test results are not always straightforward, often making them difficult to interpret and explain. Therefore, it is important that patients and their families ask questions about the potential meaning of genetic test results both before and after the test is performed. When interpreting test results, healthcare professionals take into account a person’s medical history, family history, and type of genetic test.
A positive test result means that the laboratory found a change in a particular gene, chromosome, or protein of interest. Depending on the purpose of the test, this result can confirm a diagnosis, indicating that a person is a carrier of a particular genetic mutation, identify an increased risk of developing a disease (such as cancer) in the future, or suggest the need for further testing. . Because family members have some genetic material in common, a positive test result can also have implications for certain blood relatives of the person being tested. It is important to note that a positive predictive or presymptomatic genetic test result generally cannot establish the exact risk of developing a disorder. Additionally, healthcare professionals generally cannot use a positive test result to predict the course or severity of a condition.
A negative test result means that the laboratory did not find any changes in the gene, chromosome, or protein under consideration. This result may indicate that a person is not affected by a particular disorder, is not a carrier of a specific genetic mutation, or is not at increased risk of developing a certain disease. However, the test may not have detected a genetic alteration that causes the disease because many tests cannot detect all the genetic changes that can cause a particular disorder. More tests may be required to confirm a negative result.
In some cases, a test result may not provide useful information. This type of result is called non-informative, indeterminate, inconclusive, or ambiguous. Uninformative test results sometimes happen because everyone has common natural variations in their DNA, called polymorphisms that do not affect health. If a genetic test finds a change in DNA that has not been associated with a disorder in other people, it can be difficult to tell whether it is a natural polymorphism or a disease-causing mutation. A non-informative result cannot confirm or rule out a specific diagnosis and cannot indicate whether a person is at increased risk of developing a disorder. In some cases, testing other affected and unaffected family members can help clarify this type of result.
Path to wellness
Genetic tests are not limited to helping only from a preventive and proactive perspective, but to those affected by the disease; there is a shift towards the personalized medicine paradigm of disease modeling and targeted gene therapy that has yielded excellent results. Additionally, data from the Human Genome Project has helped us understand the stratification of genes based on their penetrance levels and, in turn, help us provide a personalized risk assessment to our patients.
She is a freelance blogger, writer, and speaker, and writes for various entertainment magazines.