Considering DNA Screening Testing? Here’s a Common sense Guide.

Ireceive calls from friends, family, and their friends, asking for my advice on taking a test that assesses their risk for heart disease, cancer, or both. There are two reasons why I get these calls.

1. Someone in their family recently had an incidence of cancer or heart attack diagnosis or death.
2. Many of these enquiries are directed to me because I am a Human Genetics Scientist.

After talking to a few such people, I realised even a person with a master’s degree in science (not Human genetics) can not understand what DNA-based genetic tests are and how they help in health care. It is because we all left genetics in our choice when we were in 10th grade and thanks to crime series, we think DNA is only used to identify dead people or criminals who killed them.

To stress the importance of DNA I typically start by saying “We need to understand one simple thing i.e. DNA is the blueprint using which our body is built and operates. It is unique to every person within and outside the family. How come you do not know about DNA?”.

When people hear such statements and questions they say “You are a scientist so you understand all the science behind DNA, the test and results, but for a common man/woman like me it sounds like Latin”. During these conversations, I always remember and quote Thomas Huxley

“Science is nothing but trained and organised common sense”. — Thomas Huxley

So, what does common sense say about getting our DNA tested to know whether we will get diseases like cancer, heart attack, paralysis, diabetes, hypertension (BP), kidney disease etc.?

I ask my friends “How many diseases do you think there are?” people answer “Maybe a couple of thousand?”. Notice the question mark after their answer. None of them were able to answer the question, but it is okay. Not everyone knows how many diseases there are in the world and how many of them are infectious and how many of them are caused by genetic defects. It is one of my job responsibilities to know and answer these questions.

My next question was, “Didn’t you try to know or ask your doctor?”. Ans: “No. Why would I want to know?”

There are major obstacles to understanding or embracing the concept of DNA/genetic testing, such as knowing about disease risk and planning our future. We all believe “Ignorance is bliss” when it comes to our future health. For example, my parents did not want to get tested for diabetes. Reason, if they are diabetic they have to change their food and lifestyle habits. I know change is scary but we need to embrace it because it is the only thing that is constant in life.

Most of the time we are not serious about our health and lifestyle. We just do whatever we feel like doing and only take suggestions that we like and talk about health topics that we think are cool to talk about. Suddenly one of our friends or relatives becomes a prey to heart attack or cancer or well-known common disorders and suddenly we wake up and start researching online and calling friends like me. In that heat of the moment, people will go for health/full body check-ups. Some sales guy from/at the hospital suggests the most wonderful/powerful genetic test which will tell you all about your risk for all the diseases (btw there are more than 11k known diseases) what you should eat (nutrigenomics) and how to exercise (sports genomics) and what kind of drugs to use (pharmacogenomics). Since the cost of the test is relatively high, once again we call people like me to get to know about the usefulness of the test.

If you are serious about knowing your health risks and tackling them, then common sense says you should take preventive DNA/Genetic screening tests which can establish your risk for different diseases. However, we should take the right test.

There are two kinds of risks, absolute and baseline. When the risk is absolute the chance of getting a disease is close to certainty because nothing and no one can be 100% sure in the living world. For example, I have a mutation (change in DNA) which causes Polydactyly (extra fingers/toes) and my mother has 12 fingers and 12 toes. Considering my DNA and my family history I should have extra finger(s) or toe(s). But I don’t. But I have close to a 100% chance of getting the extra finger. (then why don’t I have it, read about genetic penetrance to know more. Wiki will do.) Now let’s imagine the same concerning cancer, I would like to know if my DNA has information about me getting cancer.

Coming to baseline risk is the relative risk of an individual getting a disease when compared to a group of people (population). For Example, both my parents, my maternal uncle and my grandparents are diabetic by the age of 45. My genetic test suggested that I have a genetic risk factor for diabetes. With all this information I have double the risk of getting Type 2 Diabetes by the time I turn 40 when compared to other people.

This all sounds exciting. Yes, decoding the information stored in our DNA is exciting and we need to take such tests only once in our lifetime. These are not like our regular blood tests whose values change with age and what we eat and our lifestyle. DNA remains unchanged throughout our lives. However, the scientific and clinical knowledge gets updated every day concerning DNA. So you can get new insights based on the latest knowledge by opting for reanalysis within a few years interval. For this you don’t need to take the test again, just your DNA data will be reanalysed. It all sounds cool, isn’t it? Nonetheless, if you are not ready to tackle the results you get from such a test, then it has no value.

We need to understand what kind of result we may get and what are the next steps after getting the results of the test. It would be good to talk to counsellors before and after taking the test.

Once again, common sense reminds us to be prepared. If you rely on luck and God for your health, remember that both favour those who are prepared. I would like to end this with a simple fact about our health. Healthy people are those who know what their limit is.

Dr Rajasekhara Reddy
Co-founder, SugarStrings.ai