However, the use of genome sequencing in healthy individuals is controversial because no one fully understands how many patients carry variants that put them at risk for rare genetic conditions and how they, and their doctors, will respond to learning about these risks.
In a paper published in the Annals of Internal Medicine, investigators at Brigham and Women’s Hospital and Harvard Medical School, along with collaborators at Baylor College of Medicine, report the results of the four-year, NIH-funded MedSeq project, the first-ever randomised trial conducted to examine the impact of whole genome sequencing in healthy primary care patients.
In the project, 100 healthy individuals and their primary care physicians were enrolled and randomised so that half of the patients received whole genome sequencing and half did not.
Nearly 5,000 genes associated with rare genetic conditions were analysed in each sequenced patient.
Among the 50 healthy primary care patients who were randomised to have their genome sequenced, 11 (22 per cent) carried genetic variants predicted to cause a previously undiagnosed rare disease.
Two of these patients were then noted to have signs or symptoms of the underlying conditions, including one patient who had variants causing an eye disease called fundus albipunctatus, which impairs night vision. This patient knew he had difficulty seeing in low light conditions but had not considered the possibility that his visual problems had a genetic cause.
Another individual was found to have a genetic variant associated with variegate porphyria, which finally explained the patient’s and family members’ mysterious rashes and sun sensitivity.
The other nine participants had no evidence of the genetic diseases for which they were predicted to be at risk. For example, two patients had variants that have been associated with heart rhythm abnormalities, but their cardiology work-ups were normal. It is possible, but not at all certain, that they could develop heart problems in the future.
“Sequencing healthy individuals will inevitably reveal new findings for that individual, only some of which will have actual health implications,” said lead author Jason Vassy, “This study provides some reassuring evidence that primary care providers can be trained to manage their patients’ sequencing results appropriately, and that patients who receive their results are not likely to experience anxiety connected to those results.”
However, continued research on the outcomes of sequencing will be needed before the routine use of genome sequencing in the primary care of generally healthy adults can be medically justified.
MedSeq project researchers said the study’s findings should be interpreted with caution because of the small sample size and because the study was conducted at an academic medical centre where neither the patients nor the primary care physicians are representative of the general population.
Questions remain about whether discovering risk markers in healthy individuals will actually provide health benefits, or will generate unnecessary testing and subsequent procedures that could do more harm than good.
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