Genome screening study flags up individuals at risk of chronic disease
Future generations could have their DNA read at birth to assess their chances of developing conditions such as heart disease and breast cancer.
A ground-breaking study has brought population-wide screening for genetic faults linked to conditions such as heart disease, diabetes and cancer a major step closer.
American scientists used information from the UK Biobank database to identify genetic variants that increase the risk of five common disorders.
The results enabled them to produce “polygenic risk scores” for more than 400,000 patients, showing how likely they were to develop one of the diseases.
In future, a similar approach could be used to identify at-risk patients at birth, say the researchers.
The conditions studied were coronary artery disease, the abnormal heart rhythm disorder atrial fibrillation, Type 2 diabetes, inflammatory bowel disease, and breast cancer.
To carry out the analysis, a computer was programmed to scour more than six million locations in the complete human genetic code, or genome.
The system identified many symptomless patients who may otherwise have been missed or only spotted at a late stage of their illness.
Notably, patients with high polygenic risk scores for coronary artery disease did not always display usual warning signs such as high blood pressure or blood cholesterol.
Cardiologist Dr Ami Khera, a member of the team from Massachusetts General Hospital in the US, said: “These individuals, who are at several times the normal risk for having a heart attack just because of the additive effects of many variations, are mostly flying under the radar.
“If they came into my clinical practice, I wouldn’t be able to pick them out as high risk with our standard metrics.
“There’s a real need to identify these cases so we can target screening and treatments more effectively, and this approach gives us a potential way forward.”
One of many predictions about the future of healthcare foresees routine genetic screening to identify individuals at risk of disease, possibly soon after birth.
Potentially life-saving treatments or preventative measures could then be applied much earlier than at present.
The new research was only made possible by the UK Biobank, a unique collection of DNA samples and medical information provided by more than 400,000 donors.
Of the anonymous participants in the study, 8% were found to be more than three times as likely to develop coronary artery disease as everyone else based on their genetic variants.
For breast cancer, the “polygenic predictor” found that 1.5% of the Biobank population had more than triple the chances of developing the disease than the rest.
Women with the highest scores were five times more at risk, meaning in absolute terms that 19% of them had breast cancer compared with about 4% of remaining individuals.
Lead scientist Dr Sekar Kathiresan, from the Broad Institute that brings together experts from the Massachusetts Institute of Technology (MIT), Harvard University and Massachusetts General Hospital, said: “We envision polygenic risk scores as a way to identify people at high or low risk for a disease, perhaps as early as birth, and then use that information to target interventions – either lifestyle modifications or treatments – to prevent disease.
“For heart attack, I foresee that each patient will have the opportunity to know his or her polygenic risk number in the near future, similar to the way they can know their cholesterol number right now.”
The research is reported in the journal Nature Genetics.
