Will Predictive Genomics Bring A Patient-Empowered Future?

Breakthroughs in molecular diagnostics are bringing us close to an era in healthcare often referred to as ‘Personalized Medicine’ where soon molecular markers will point towards a person’s risk of developing a disease, determine whether a person is a carrier of a hereditary condition, screen for diseases that are present but not yet symptomatic, confirm a diagnosis, or monitor how a patient is responding to treatments.

The genome comprises all of our deoxyribonucleic acid (DNA), which carries our genetic information. The DNA molecule contains four chemical units, expressed in letters A, T, G and C. Whole Genome Sequencing (WGS) looks at the order of three billion pairs of these letters. There are around 20,000 genes (made of DNA) in every cell of our body, which act as instructions to make molecules called proteins, which then determine the structure and functioning of our cells, tissues and organs. Mutation in any one of these genes on their own or in combination with mutations in other genes or with environmental factors can cause a disease.

With access to genetic data sets, as well as technological advances, such as Next Generation Sequencing, scientists are getting better at understanding the implications of these genetic variations in various diseases and disorders. These are promising signs, pointing to a new, technology-empowered future. Today, genetic tests in India can cost anywhere between Rs 3,000 for something like thalassemia and Rs 1 lakh for whole genome sequencing (WGS). These tests are expensive as most of the devices that are used to perform these tests in India are imported from other countries.

But even though we know that the ability to detect minuscule amounts of circulating DNA from pathological sources is poised to have a clinically meaningful impact, there remain a few practical as well as ethical questions to be answered. Can a genetic test really predict your health outcomes? Do you want to know today whether you are at high risk of a disease whose onset may be three decades from now? If the genetic test comes out positive for a terminal disease that has no cure, what would you do? In a country where “out of pocket” expenditure is a major part of your healthcare spends, is getting a genetic test done a luxury or a necessity? And if it is a necessity, is the government willing to play a role in making these life-saving tests affordable and accessible? As we address these tough questions, we need to also understand that in India there are multiple patient barriers when it comes to preventive checks those are beyond affordability, and predictive genomic tests being a higher order of preventive care will take some time before having a meaningful impact.

Even though the year 2019 witnessed significant developments in the preventive space, there is an urgent need for the government to accelerate further reforms and supportive measures in 2020 to make India a global genetic test device manufacturing hub, reduce import dependency in this segment and make personalized genomic treatment affordable and accessible to the masses at large.

Under personalized genomic medicine, the aim is to individualize treatment and empower patients to take more responsibility for their own health. At the core of this concept is the understanding that we are all different, with different biological make-ups and environments. Therefore a one-size-fits-all approach to diagnostics and treatment will soon become out of date.

Researchers on other hand are seriously working towards building something meaningful that all doctors will want to recommend and all of the population will want to experience. The most recent cutting-edge approach in the hunt for actual genetic contributors to common diseases is polygenic risk scores. Still there’s a long way to go, experts feel polygenic scores could be the next great stride in genomic medicine. Once successfully validated across different populations, polygenic scores will enable clinicians to pick out individuals who fly under the risk radar for specific diseases/disorders.

However, like the probability of rain in tomorrow’s weather forecast, polygenic scores have inherent uncertainty. Appreciating this uncertainty is the key because the uncertainty in polygenic scores leaves room for action. We know that for many complex diseases behavior is just as important as genes in setting the stage for what is to come. Since disease onset isn't solely determined by genes, lifestyle or therapeutic interventions can prevent or modify the trajectory of disease.

This brings us to the understanding that genes never work in isolation. Instead, they determine how we react to our diet, social surroundings, physical environment, infections, chemical exposures and medicines. Furthermore, in most diseases, factors such as environment, diet and lifestyle work in combination with genetics. Understanding how these factors affect your health will empower people to make the changes in their lifestyle that will matter most. To understand what food to eat, which chemicals to avoid, what exercise regimen to follow, etc. All the pieces to solve this puzzle must come together. And when that happens, genetic medicine is going to become much more precise and, ultimately, far more personalised.