Dr Ramesh Hariharan, CEO and Co-Founder, Strand Life Sciences highlights the role and upcoming trends of genetic testing in preventive healthcare
Over the last ten years, the field of genomics has made significant advancements. The more than 10-fold reduction in the cost of genome sequencing has led to much research as well as the development of clinical-grade genomic testing for a variety of purposes, including the diagnosis of rare diseases, prediction of cancer risk, and personalisation of cancer treatments. However, these are just a few examples , and there are many more developments on the horizon.
In particular, rising adoption of healthier lifestyles and growing awareness about the benefits of genomic testing are triggering interest in genomic-based tests for preventive wellness. Such tests assess an individual’s risk of developing certain health conditions that have a strong genomic component. The adage “Forewarned is forearmed” applies here; these tests can provide valuable information to help individuals take steps to prevent disease onset or delay disease progression. Preventive genomic testing is expected to gain significant traction in the coming years.
Increasing interest in preventive genetic testing
Around a decade ago, preventive genomic testing gained widespread attention when Hollywood actress Angelina Jolie disclosed that genetic testing had revealed she had an 87 per cent risk of breast cancer and a 50 per cent risk of ovarian cancer due to a genetic variant in the BRCA1 gene. This is significantly higher than the average woman’s lifetime risk of under 15 per cent for breast and ovarian cancer. As a result of this information, Jolie underwent preventive surgery, which reduced her risk to that of the average woman of her age. Chris Hemsworth’s high risk of Alzheimer’s Disease and Sergei Brin’s risk of Parkinson’s disease are other high profile examples of individuals who have chosen to get tested for impending risk so they can take actions to mitigate this risk.
Promoting universal screening: The role of preventive genomics
For many years, medical guidelines have only recommended preventive genomic testing for individuals who are at a higher risk of developing cancer, such as family members of cancer patients. However, research has indicated that this approach misses more than half of those at risk, leading to calls for universal screening. The cost of testing has also significantly decreased, with prices dropping from thousands of dollars a decade ago to around $150 today. Health economic studies have shown that 250,000 lives in India can be saved if all women were to be screened preventively for cancer causing inherited mutations.
In a report that highlighted the benefits of genetic testing in healthy individuals, Mayo clinic observed that the number of people who opted for predictive genomic testing at the clinic increased from 11 per cent in 2014 to 40 per cent in 2019. One in eight individuals who opted for predictive genetic testing found that they were at a risk for clinically actionable conditions like cancers, cardiac diseases and genetic conditions that influenced their family planning decisions.
Expanding the horizons of preventive genomic testing: Applications beyond cancer
While the most actionable risk found by preventive testing in the Mayo report above was for cancer, there are several other health conditions that can be detected earlier using preventive genomic testing. In particular, studies on sudden unexplained death of apparently healthy individuals show that 13 per cent-15 per cent of such individuals have genomic variants that cause silent cardiac conditions (channelopathies, cardiomyopathies). If these genomic variations are detected early, it can potentially be life-saving
In addition to identifying an individual’s own risk of disease, preventive genomic testing can also provide insights into the risk of disease in one’s offspring. For example, in India, approximately 1 in 25 individuals are carriers of Beta-thalassemia, a condition that requires lifelong blood transfusions. There are several such diseases, e.g., Cystic Fibrosis, Congenital Deafness, Inborn errors of Metabolism etc. If detected early through genomic testing, appropriate measures and treatment can be initiated to avoid or manage the condition.
Future of preventive genomics: What to expect
Genomic testing typically involves analyzing the inherited genome, or the genetic information that a person is born with. Interpreting the tens of thousands of individual variants that might affect a person needs to be done with care because the impact of many of these variants is yet unknown. Responsible reporting requires restricting risk prediction to high confidence variants. Labs in India, have started offering simple doorstep sample collection, evaluation of close to 20,000 genes to give an individual key insights into his/her genomic risk, as well as archival of this data for future reinterpretation as knowledge progresses.
However, the genome can also undergo changes over the course of an individual’s lifetime, known as epigenetic changes. These changes can be indicative of certain diseases and can often be detected through a simple blood draw, making it possible to detect conditions like cancer early and non-invasively. The study of epigenetic changes is an area of active research and is expected to play a significant role in the future of genetic testing and disease detection.
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