5 Facts About Genetic Testing

Genetic testing is a type of medical test that examines your DNA – the chemical molecules which carry all instructions on how your body should develop and function. There are more than 77,000 different types of genetic tests in use, with many others in the works. Find out 5 facts about genetic testing that you ought to know.

Since the technology was first discovered and utilised in the 1950s, it has become a more affordable medical tool used commonly in healthcare settings. It has been estimated that Asia will be the fastest growing region for genetic testing in the coming 5 years.  This article will shed some light on genetic testing. 

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1. Why Is Genetic Testing Done? 

• Diagnostic purpose: usually prescribed by doctors. If you have symptoms of a certain disease which has a strong genetic link, the test could help doctors with diagnosis. 
• Carrier testing: if one or some of your family members have genetic conditions, your doctor might prescribe certain genetic tests to check if you carry the gene for the inheritable disorders too.
• Prenatal testing: many countries’ healthcare systems mandate or strongly advise pregnant women to undergo prenatal genetic screening tests to determine the risk of having a baby with certain congenital diseases. Parents-to-be can then plan for appropriate care. 
• Personal interest: I want to know more about myself! Great, there are dozens of different DIY genetic testing kits available on the market, usually costing around 50 to 300 USD. These purport to reveal ancestry, personality or behavioural traits, and also guide personal wellbeing e.g. for personalisation of diet or supplements.

2. What Type of Genetic Test Should I Go For?

The approach to genetic testing is individualised based on your medical and family history, and purpose. Here are some of the common types available: 

• Single gene testing: if your doctor suspects you have a condition linked to a specific known gene, this test could be done to investigate whether there is abnormality with that gene. 
• Whole genome sequencing: this examines all the DNA in your body. It is used medically when single gene testing fails to provide diagnosis or in patients with complex medical histories necessitating more extensive analysis.
• Chromosome test: human DNA is packed in structures called chromosomes. Chromosomal structural changes can result in genetic conditions (e.g. Down Syndrome) as well. Chromosome test is used to investigate chromosomal abnormalities.

3. How Is Genetic Testing Done?

Depending on the test selected, a sample of your blood, hair, skin, cheek swab, amniotic fluid, placental tissue etc. will be sent to a lab for analysis. 

4. How Do I Interpret The Results Of My Genetic Tests? 

As mentioned before, the DIY kits available on the market do not offer medical suggestions or diagnosis. Results are general in nature, but you can make lifestyle changes accordingly based on the results. Genetic testing for medical purposes must go through a trained healthcare professional in most jurisdictions. 

Specialised genetic testing usually has three results: positive, negative or inconclusive. 

• Positive: This means the test detected a change in the gene(s) of interest. It could translate as either susceptibility to, or presence of a certain disease. 
• Negative: This means the test did not detect a change in certain disease-causing gene(s). However, this may not translate with 100% certainty to not having, or not developing the disease.
• Inconclusive: Sometimes there may be variants of uncertain significance; it can be difficult to determine if they are benign or potentially disease-causing. Further testing may be required.

Essentially, genetic testing is not the be all and end-all of diagnosing conditions, but a supplementary tool. The results should be discussed with a medical practitioner for the best way forward.

5. What Are The Pros And Cons Of Genetic Testing? 

Pros include: 

• Relief from uncertainty
• Better understanding of your health status/risks
• Better able to make informed medical and lifestyle choices
• Opportunity to educate family members about potential risks

Cons include:

• Inconclusive results even after multiple different kinds of tests. However, with rapidly evolving technology and research, the emergence of more reliable tests may not be too distant a future. 
• Psychological and emotional stress. People may feel angry, depressed, or guilty about the results. Carrier tests in some cases can also create tensions in the family. 

Conclusion

As genetic testing may present considerable ramifications, consult a doctor to discuss the pros and cons carefully before deciding whether it is the best for you and your family.

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