The genetics researcher: Mark Caulfield

A CT scan of the heart and its blood supplyProfessor Mark Caulfield is Director of the William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, London. His research aims to discover which genes cause high blood pressure, in order to prevent premature heart attacks and strokes caused by hypertension.

I’ve studied families and their genes since the 90s. We each have about three billion ‘letters’ in our genetic code and about every 300th letter there’s a random change or variation in the code.

These  variations are what make us individuals, but sometimes they can also leave us vulnerable to disease. So far the gene variations that make us susceptible to conditions such as hypertension are fairly common – more than five in every 100 people will have them.

We’ve known for some time that essential hypertension (hypertension which is caused by a mixture of genes and lifestyle) runs in families and that there are multiple genes that can affect blood pressure.

Scientists have studied adults who were adopted at birth and discovered that their blood pressure level is more likely to be similar to that of their genetic parents than to their adopted parents. So while lifestyle does affect our risk of high blood pressure, our genetic make-up also plays a role. This means our risk of hypertension will be influenced by a complex interaction between lifestyle and genes.

Mark CaulfieldOur most recent research involved more than 200,000 participants. We learned that while individual changes in the genetic code often have a very modest effect on blood pressure, a combination of several genetic variations that affect blood pressure have a much bigger effect.

Some combinations of genetic variations can have a beneficial effect, lowering blood pressure, while others raise it. So if you have 40 or more genetic variations that increase blood pressure, you’ll almost definitely develop hypertension as an adult, increasing your risk of a heart attack or stroke.

By studying the genetic variations involved in hypertension, we hope to answer two important questions: can we find new treatments for hypertension through understanding the genetic factors and can we use genetic variations to predict response to medicines and select the best treatment for a patient? A third, more challenging, question is who’s likely to develop it in the future and can we prevent it? If we could answer these questions, it would help us to develop drugs targeted to the cause of high blood pressure.

What it means for you

The exciting news is that there are some drugs molecules already produced, which we think have potential to block the action of some of the genes already known to cause hypertension. So rather than giving everyone the same cocktail of drugs, we could prescribe drugs that are most likely to be effective for a person’s genetic make-up.

But much more research needs to be carried out. First, we’d have to test whether the drugs would be safe and effective in people with certain genetic variations. Second, genetic testing would need to become more accessible.

Thanks to funders like the BHF, we hope that within five years we’ll have a much better understanding of how our genes affect our risk of high blood pressure and what to do about it. But whatever we find, genetic testing will never replace the need for a standard blood pressure test. In the meantime, if you have high blood pressure, keep taking your medication and live as healthily as you can.