Genomics, the study of DNA and RNA and how genetic variation influences health and disease, can help explain why a medicine works, has little effect, or causes harmful side effects. Despite this, its role in prescribing remains poorly understood across health and care.
In the first of four conversations, Health Innovation Network South London Medical Director Dr Natasha Curran asks Professor Sean Whittaker, Medical Director of the South East Genomic Medicine Service, whether genomics should still be seen as a specialist discipline, where it is already being used and what its growth could mean for patients.
Natasha: Let’s begin with the basics. What do we mean by genomics?
Sean: Genomics is the study of DNA and RNA, and of how genetic variation influences health and disease. It encompasses inherited disease, cancer biology and risk prediction, as well as the increasingly important question of how patients respond to treatment. At its heart, genomics helps us understand the biology of disease.
Natasha: Most doctors probably don’t think of themselves as practising genomic medicine. Are many of them already doing so without necessarily realising it?
Sean: In many specialities, they absolutely are. Oncology is the most obvious example. Virtually every patient with cancer now undergoes testing to understand the biology of their tumour. Paediatrics has also been practising genomic medicine for many years, particularly when investigating developmental delay and complex conditions.
Natasha: Can you give us a sense of the scale of genomic testing now, and how quickly it is growing?
Sean: The South East Genomic Medicine Service covers almost 10 million people and currently performs around 125,000 tests each year. We expect that figure to rise to approximately 250,000 tests annually within the next few years.
Natasha: What has driven that growth over the past five years?
Sean: Following the 100,000 Genomes Project, the NHS has focused on expanding the service rapidly, improving turnaround times and increasing efficiency. There has also been a huge educational challenge, because genomics is now relevant to doctors, nurses, midwives and many other health professionals.
Natasha: If genomics is already part of so much clinical practice, what is the biggest misconception about it?
Sean: Many people assume that finding a genetic variant automatically means you have found the cause of a disease. In reality, we all carry multiple genetic variants. The challenge is working out which of them are genuinely clinically relevant.
Natasha: Could genomics also change how we assess the risk of common conditions, such as cardiovascular disease?
Sean: Potentially, yes. Genomic medicine is already used to identify inherited conditions such as familial hypercholesterolaemia, or FH. In future, we may be able to combine genomic information with traditional risk assessments. Rather than looking only at cholesterol levels, blood pressure and lifestyle factors, clinicians could use an integrated risk score that also takes a person’s genetic information into account.
Natasha: What might that mean for an individual patient?
Sean: Someone who appears to be at relatively low cardiovascular risk using current assessment tools may turn out to have a much higher underlying genetic risk. In future, that could influence decisions about preventive treatments such as statins and allow us to target interventions more precisely.
But identifying risk is only part of the story. The key question is whether we can actually reduce it. There is little value in testing large populations if we do not have effective interventions that improve outcomes. For genomics to become part of routine prevention programmes, it will need to demonstrate clear clinical benefit as well as good value for money.
Natasha: What other challenges could arise as genomic medicine moves into mainstream healthcare?
Sean: One is that much of the genomic data available to us comes from populations of European ancestry. That means genomic risk tools may currently be more accurate for some populations than for others. As genomic medicine expands, we need to ensure that it benefits all communities equally. Otherwise, there is a danger that innovation could inadvertently widen health inequalities rather than reduce them.
Affordability is another important consideration. Genomic testing may identify people at increased risk of disease, but health systems must also ask whether acting on those results produces enough improvement in outcomes to justify the investment. Identifying risk is only the first step; the challenge is ensuring that genomic medicine improves health at both an individual and a population level.
Natasha: Looking ahead, where is genomic medicine heading?
Sean: Cancer genomics will become increasingly sophisticated, pharmacogenomics will have a growing influence on prescribing decisions, and population health genomics will continue to develop wherever risk can be meaningfully modified.
In the next blog, Natasha and Sean explore pharmacogenomics: how our genes can affect the way we respond to medicines.
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