An introduction to genomic medicine and DNA health tests

DNA health tests are on the rise, but what can they tell us and how will they be used to make us healthier?

Across the globe, lifestyle-related diseases like cardiovascular disease and cancer continue to grow more prevalent, putting a huge strain on health systems. It’s clear that current approaches to health promotion are not sufficient to effect behavioural change on a large scale.

But perhaps large-scale change is not the point. Perhaps the health industry needs to focus more on the micro-level, on changing health behaviours one person at a time. Today it is more possible than ever to take a highly targeted approach to changing behaviours. The advent of big data analysis, DNA testing and interactive health engagement is moving us ever closer to an age of personalised medicine that is both more effective and more cost-effective than today’s healthcare model.

From passive to active

There are already high-profile cases of individuals who have had DNA health tests that have resulted in life-saving/preventative surgery or led them to implement significant lifestyle changes. These stories highlight a fundamental shift in healthcare.

Rather than being passive recipients of health services, some individuals are taking more responsibility for their own care and are playing a more active role in their own health management. As the Quebec Network for Personalized Health Care has put it: “In the new paradigm, the patient will become a citizen.”

But they won’t be “citizens” of demand-driven legacy healthcare systems. Instead, they’ll engage with value-based systems offering care that is:

The 4Ps health care model

Predictive: Genetic profiles and other personal information will help doctors identify individual risk factors and choose just the right methods and treatments to monitor a patient’s risk of developing certain diseases and conditions.
Personalised: Clinical interventions will be based on each individual’s unique genetic, medical and environmental conditions.
Participatory: Individuals will become partners in their own care, and clinicians will use a range of tools to keep them engaged outside the doctor’s office and hospital.
Preventative: Personalised methodologies and treatments will enable people to take appropriate measures to help them stay fit and well as they age.

Aetna International DNA Infographic Clinical Input, Tech Input and Predictive Personalised Intervention

The cost of DNA tests

One factor changing the face of health promotion and disease prevention is the advent of relatively inexpensive DNA testing — some expect the cost to sequence a genome to fall below $100 in the future.

Types of genetic tests

What exactly is genetic testing? And what can a DNA test tell me? According to the U.S. National Human Genome Research Institute, genetic testing “uses laboratory methods to look at your genes, which are the DNA instructions you inherit from your mother and your father. Genetic tests may be used to identify increased risks of health problems, to choose treatments or to assess responses to treatments.”

There are hundreds of different tests available, from prenatal screening that determines the likelihood of birth defects to forensic testing that can implicate a crime suspect. These tests look at all or part of the human genome, a string of some 3.2 billion nucleotide pairs that affect everything from hair colour to disease risk. Not all genetic tests look at the entire human genome, however.

Clinically relevant tests fall into three categories:

Whole-genome sequencing looks at the entire genome, as the name implies
Whole-exome sequencing looks at the regions of DNA that code for proteins, approximately 2 per cent of the whole genome
Genotyping looks at regions of DNA that are associated with specific characteristics, approximately 0.03 per cent of the whole genome.

Genotyping offers a window into your paternal and maternal lineage and can potentially tell you what percentage of your makeup is Irish, Scandinavian or South-East Asian. Some tests also report fun facts such as your likelihood of having blue eyes (something you already know), losing your hair (something you may fear) or having waxy ears (something you’d probably not want to share at a dinner party). Most direct-to-consumer services like AncestryDNA offer genotyping, although a few are beginning to offer more extensive tests. For example, a firm called Veritas now offers whole-genome sequencing for $999 (with physician approval). The company promises insights on more than 1,200 hereditary diseases, 200 drug responses and 70 physical traits.

What does a DNA health test tell me?

Generalised tests normally report genetic variations or gene variants that are associated with changes that have a minor impact on function and can be influenced by lifestyle and diet choices. (Remember that lifestyle choices are a bigger factor in premature deaths than genetics.) At times, tests can indicate the potential for developing cancer or rare diseases like sickle cell anaemia and cystic fibrosis; in such cases medical and/or genetic counselling resources are necessary, as the results can be complex, difficult for consumers to understand and potentially distressing.

Counselling will also help individuals avoid any self-diagnosis without medical intervention. It must also be noted that the presence of a genetic marker doesn’t mean the associated disease will ever develop, just that the odds of it appearing may be somewhat higher. As Bert Vogelstein, director of the Ludwig Center for Cancer Genetics and Therapeutics at Johns Hopkins University, says: “Whole-genome testing is not a crystal ball. It may become one important determinant in patient care, but certainly not the only one – and possibly not even a major one.”

If you’re an employer who would like to know more about international private medical insurance (iPMI) or DNA testing for your international employees, get in touch with a team near you.