New DNA tests predict your disease risk – are we ready for them?

IT SOUNDS too good to be true: a medical test that can detect diseases you may develop decades from now. Suitably forewarned, you can take immediate steps to reduce your risk.

This is the promise of polygenic tests, so named because they involve sequencing multiple parts of someone’s DNA. They are being developed for a growing number of diseases, and advocates claim that they could revolutionise medicine by helping people avoid everything from type 1 diabetes to heart attacks and cancer. “If we can shift the focus to prevention, we could get a fundamentally different approach to healthcare,” says John Bell at the University of Oxford, who recently helped launch a massive pilot scheme in the UK involving the National Health Service.

It would be a big leap forward. Until now, we have only been able to predict someone’s risk of getting rare diseases caused by single genes. But soon we will be able to predict how likely you are to get the far more common conditions caused by multiple genes.

Yet some critics say this new era of preventive medicine is being rushed in without proper consideration of the consequences – for the people getting their risk scores and for healthcare systems. “These tests have benefits, but they also have risks and adverse events,” says Amit Sud at The Institute of Cancer Research in London.

What is clear is that with several polygenic risk tests already on sale to the public, we need to weigh up the costs and benefits from the impending uptake before it is too late.

Claims that genetics is about to transform medicine have been made …