Genome sequencing the ability to sequence an individual's DNA is becoming a standard tool to study diseases. In 2019, over 26 million people took direct-to-consumer DNA tests, which speaks to our collective desire to better understand our genomes.
In July 2013, the American College of Medical Genetics and Genomics issued a recommendation that people who have their genomes sequenced in a clinical setting should also have their genomic data screened for variants in 56 genes that can pose health risks. The genes (which includes the RET gene) are associated with increased risks for several life-threatening, but treatable or preventable diseases. The number of genes included in the list increased to 59 in 2016, and clinicians expect that the list will be updated again soon.
When a person comes into the clinic to be tested for a specific condition, any positive result related to that condition is called a primary finding. But when testing reveals information separate from the original condition, it is called a secondary finding. An estimated 1-4% of people receive unexpected health results from genomic tests each year.
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Animation of a clinician explaining primary and secondary findings. Credit: Harry Wedel, NHGRI.
Secondary findings are not unique to clinical genomics. People can also receive secondary findings from MRI, radiology and other medical tests.
In the case of genome sequencing, examples of secondary findings can include those related to the BRCA1 and BRCA2 genes, which are associated with breast and ovarian cancer risk, and conditions such as inherited heart rhythm problems. Clinicians share such secondary findings with a person only if the person consents to receiving such information.
Secondary findings are now a component of precision medicine, relying on individual and collective genomic data to make assessments about a persons health risks. Clinicians can obtain highly accurate findings because of the vast amount of available genome sequence data. Researchers can search this data to improve genomic testing and how they detect people who are at risk of harboring disease-related variants. Specifically, secondary findings provide individuals and families the opportunity to learn about their health risks before they develop a disease.
In 2019, researchers at the National Human Genome Research Institute (NHGRI) started the Genomic Services Research Program, part of what is now NHGRI's Center for Precision Health Research, to further understand and improve the implementation of precision medicine initiatives.
"Secondary findings play a pivotal role in diagnosing diseases, preserving health and saving lives," said Leslie Biesecker, M.D., chief of the NHGRIs Clinical Genomics Section. "Our research program measures how clinicians communicate these findings and peoples reactions so we can identify areas for improvement. The payoff could improve human health by making it commonplace for people to get treatment for diseases before they are sick."
The payoff could improve human health by making it commonplace for people to get treatment for diseases before they are sick.
According to Biesecker, identifying a secondary finding is only the first step. The Genomic Services Research Program studies whether secondary findings have real-life use and value by assessing three key components:
Biesecker also emphasized the need for healthcare providers to clearly communicate with patients who receive secondary findings so they understand their treatment options.
"Most people seek out genetic testing because they know of a strong family history for a certain disease," said Katie Lewis, Sc.M., CGC, a genetic counselor in the program. "But for those individuals who get these secondary findings, it can be an immense surprise. Our goal is to help individual patients get the care they need and share the result with their families.
Lewis also adds that there is very little known about the extent to which patients follow through with treatment and the factors that influence their decisions. Understanding what motivates those who do take action and those who do not can help genetic counselors target their efforts to assist an individual with a secondary finding and translate it into improved long-term health.
Recommendation and review posted by G. Smith