PATIENTS’ GENES BEING USED TO IMPROVE CARE

GENETIC testing raises the possibility of healthy people finding out what diseases they are more likely to develop, from heart disease to cancer. With this information they can take steps — such as lifestyle changes or medical treatment — to reduce their risk.

It’s also being used in some patients already diagnosed with a condition to tailor their treatment to fit their genetic blueprint.

This ‘personalised medicine’ is being trialled by the NHS (see main story) for stroke and heart attack risk, but there are other DNA tests already available on the NHS and privately.

For example, the BRCA gene test is used by the NHS to identify healthy women at increased risk of breast and ovarian cancer. The blood test can also be used to identify men at risk of prostate cancer, and is available to anyone with a family history of the disease.

Since the test was introduced more than 20 years ago, hundreds of thousands of women at higher risk of breast cancer have been identified. In some cases, they’ve chosen to have a preventative mastectomy — as Angelina Jolie did in 2013 after testing positive for faulty BRCA genes.

Genetic testing is also available to check for the risk of hypertrophic cardiomyopathy, a thickening of the heart muscle and a cause of sudden cardiac death and some heart rhythm problems. This screening is offered to those with a family history of the disease, but it’s not perfect because not all the relevant genes have been identified.

Other DNA tests available on the NHS include one for Huntington’s Disease, an inherited condition that affects the brain and nervous system. Private companies offer genetic tests ‘screening’ for a range of diseases, including Parkinson’s and dementia, although the increased risk from having certain genes may be small.

DNA tests can be used to predict disease progression, too. For instance, the Oncotype DX test predicts the chance of breast cancer recurring by looking at the activity of 21 key genes in cancer tissue (it is one of three tests, along with EndoPredict and Prosigna, used by the NHS).

Genetic testing is also useful when deciding how to treat cystic fibrosis and inflammatory bowel disease, by identifying how well the body metabolises a drug — or whether it will work at all.