News, Analysis, Trends, Management Innovations for
Clinical Laboratories and Pathology Groups

Hosted by Robert Michel

News, Analysis, Trends, Management Innovations for
Clinical Laboratories and Pathology Groups

Hosted by Robert Michel
Sign In

Broad Institute/Massachusetts General Hospital Researchers Develop Multi-Gene Test That Identifies Those at High Risk for Developing Heart Disease and Four Other Potentially Deadly Conditions

Next step is to design Web portal offering low-cost ‘polygenic risk score’ to people willing to upload genetic data received from DNA testing companies such as 23andMe

Pathologists and other medical professionals have long predicted that multi-gene diagnostics tests which examine thousands of specific gene sequences might one day hold the key to assessing disease risk, diagnosing diseases, and guiding precision medicine treatment decisions. Now, a research team from the Broad Institute, Massachusetts General Hospital (MGH) and Harvard Medical School have brought that prediction closer to reality.

Their study, published last month in Nature Genetics, found that a genome analysis called polygenic risk scoring can identify individuals with a high risk of developing one of five potentially deadly diseases:

  • Coronary artery disease;
  • Atrial fibrillation;
  • Type 2 diabetes;
  • Inflammatory bowel disease; and,
  • Breast cancer.

Polygenic Scoring Predicts Risk of Disease Among General Population

To date, most genetic testing has been “single gene,” focusing on rare mutations in specific genes such as those causing sickle cell disease or cystic fibrosis. This latest research indicates that polygenic predictors could be used to discover heightened risk factors in a much larger portion of the general population, enabling early interventions to prevent disease before other warning signs appear. The ultimate goal of precision medicine.

“We’ve known for long time that there are people out there at high risk for disease based just on their overall genetic variation,” senior author Sekar Kathiresan, MD, co-Director of the Medical and Population Genetics Program at the Broad Institute, and Director, Center for Genomic Medicine at Massachusetts General Hospital, said in a Broad Institute news release. “Now, we’re able to measure that risk using genomic data in a meaningful way. From a public health perspective, we need to identify these higher-risk segments of the population, so we can provide appropriate care.”

“What I foresee is in five years, each person will know this risk number—this ‘polygenic risk score’—similar to the way each person knows his or her cholesterol,” Sekar Kathiresan, MD (above), Co-Director of the Medical and Population Genetics Program at the Broad Institute, and Director, Center for Genomic Medicine at Massachusetts General Hospital, told the Associated Press (AP). He went on to say a high-risk score could lead to people taking other steps to lower their overall risk for specific diseases, while a low-risk score “doesn’t give you a free pass” since an unhealthy lifestyle can lead to disease as well. (Photo copyright: Massachusetts General Hospital.)

The researchers conducted the study using data from more than 400,000 individuals in the United Kingdom Biobank. They created a risk score for coronary artery disease by looking for 6.6 million single-letter genetic changes that are more prevalent in people who have had early heart attacks. Of the individuals in the UK Biobank dataset, 8% were more than three times as likely to develop the disease compared to everyone else, based on their genetic variation.

In absolute terms, only 0.8% of individuals with the very lowest polygenic risk scores had coronary artery disease, compared to 11% for people with the highest scores, the Broad Institute news release stated.

“The results should be eye-opening for cardiologists,” Charles C. Hong, MD, PhD, Director of Cardiovascular Research at the University of Maryland School of Medicine, told the AP. “The only disappointment is that this score applies only to those with European ancestry, so I wonder if similar scores are in the works for the large majority of the world population that is not white.”

In its news release, the Broad Institute noted the need for additional studies to “optimize the algorithms for other ethnic groups.”

The Broad Institute’s results suggest, however, that as many as 25 million people in the United States may be at more than triple the normal risk for coronary artery disease. And millions more may be at similar elevated risk for the other conditions, based on genetic variations alone.

Reanalyzing Data from DNA Testing Companies

The researchers are building a website that would enable users to receive a low-cost polygenic risk score—such as calculating inherited risk score for many common diseases—by reanalyzing data users previously receive from DNA testing companies such as 23andMe.

Kathiresan told Forbes his goal is for the 17 million people who have used genotyping services to submit their data to the web portal he is building. He told the magazine he’s hoping “people will be able to get their polygenic scores for about as much as the cost of a cholesterol test.”

Some Experts Not Impressed with Broad Institute Study

But not all experts believe the Broad Institute/MGH/Harvard Medical School study deserves so much attention. Ali Torkamani, PhD, Director of Genomics and Genome Informatics at the Scripps Research Translational Institute, offered a tepid assessment of the Nature Genetics study.

In an article in GEN that noted polygenic risk scores were receiving “the type of attention reserved for groundbreaking science,” Torkamani said the recent news is “not particularly” a big leap forward in the field of polygenic risk prediction. He described the results as “not a methodological advance or even an unexpected result,” noting his own group had generated similar data for type 2 diabetes in their analysis of the UK dataset.

Nevertheless, Kathiresan is hopeful the study will advance disease treatment and prevention. “Ultimately, this is a new type of genetic risk factor,” he said in the news release. “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.”

This latest research indicates healthcare providers could soon be incorporating polygenic risking scoring into routine clinical care. Not only would doing so mean another step forward in the advancement of precision medicine, but clinical laboratories and pathology groups also would have new tools to help diagnose disease and guide treatment decisions.

—Andrea Downing Peck

Related Information:

Genome-wide Polygenic Scores for Common Diseases Identify Individuals with Risk Equivalent to Monogenic Mutations

Predicting Risk for Common Deadly Diseases from Millions of Genetic Variants

Multigene Test May Find Risk for Heart Disease and More

A Harvard Scientist Thinks He Has a Gene Test for Heart Attack Risk. He Wants to Give It Away Free

Why Do Polygenic Risk Scores Get So Much Hype?

Polygenic Scores Show Potential to Predict Humans’ Susceptibility to a Range of Chronic Diseases; New Clinical Laboratory Genetic Tests Could Result from Latest Research

Access to vast banks of genomic data is powering a new wave of assessments and predictions that could offer a glimpse at how genetic variation might impact everything from Alzheimer’s Disease risk to IQ scores

Anatomic pathology groups and clinical laboratories have become accustomed to performing genetic tests for diagnosing specific chronic diseases in humans. Thanks to significantly lower costs over just a few years ago, whole-genome sequencing and genetic DNA testing are on the path to becoming almost commonplace in America. BRCA 1 and BRCA 2 breast cancer gene screenings are examples of specific genetic testing for specific diseases.

However, a much broader type of testing—called polygenic scoring—has been used to identify certain hereditary traits in animals and plants for years. Also known as a genetic-risk score or a genome-wide score, polygenic scoring is based on thousands of genes, rather than just one.

Now, researchers in Cambridge, Mass., are looking into whether it can be used in humans to predict a person’s predisposition to a range of chronic diseases. This is yet another example of how relatively inexpensive genetic tests are producing data that can be used to identify and predict how individuals get different diseases.

Assessing Heart Disease Risk through Genome-Wide Analysis

Sekar Kathiresan, MD, Co-Director of the Medical and Population Genetics program at Broad Institute of MIT/Harvard and Director of the Center for Genomics Medicine at Massachusetts General Hospital (Mass General); and Amit Khera, MD, Cardiology Fellow at Mass General, told MIT Technology Review “the new scores can now identify as much risk for disease as the rare genetic flaws that have preoccupied physicians until now.”

“Where I see this going is that, at a young age, you’ll basically get a report card,” Khera noted. “And it will say for these 10 diseases, here’s your score. You are in the 90th percentile for heart disease, 50th for breast cancer, and the lowest 10% for diabetes.”

However, as the MIT Technology Review article points out, predictive genetic testing, such as that under development by Khera and Kathiresan, can be performed at any age.

“If you line up a bunch of 18-year-olds, none of them have high cholesterol, none of them have diabetes. It’s a zero in all the columns, and you can’t stratify them by who is most at risk,” Khera noted. “But with a $100 test we can get stratification [at the age of 18] at least as good as when someone is 50, and for a lot of diseases.”

Sekar Kathiresan, MD (left), Co-Director of the Medical and Population Genetics program at Broad Institute at MIT/Harvard and Director of the Center for Genomics Medicine at Massachusetts General Hospital; and Amit Khera, MD (right), Cardiology Fellow at Mass General, are researching ways polygenic scores can be used to predict the chance a patient will be prone to develop specific chronic diseases. Anatomic pathology biomarkers and new clinical laboratory performed genetic tests will likely follow if their research is successful. (Photo copyrights: Twitter.)

Polygenic Scores Show Promise for Cancer Risk Assessment

Khera and Kathiresan are not alone in exploring the potential of polygenic scores. Researchers at the University of Michigan’s School of Public Health looked at the association between polygenic scores and more than 28,000 genotyped patients in predicting squamous cell carcinoma.

“Looking at the data, it was surprising to me how logical the secondary diagnosis associations with the risk score were,” Bhramar Mukherjee, PhD, John D. Kalbfleisch Collegiate Professor of Biostatistics, and Professor of Epidemiology at U-M’s School of Public Health, stated in a press release following the publication of the U-M study, “Association of Polygenic Risk Scores for Multiple Cancers in a Phenome-wide Study: Results from The Michigan Genomics Initiative.”

“It was also striking how results from population-based studies were reproduced using data from electronic health records, a database not ideally designed for specific research questions and [which] is certainly not a population-based sample,” she continued.

Additionally, researchers at the University of California San Diego School of Medicine (UCSD) recently published findings in Molecular Psychiatry on their use of polygenic scores to assess the risk of mild cognitive impairment and Alzheimer’s disease.

The UCSD study highlights one of the unique benefits of polygenic scores. A person’s DNA is established in utero. However, predicting predisposition to specific chronic diseases prior to the onset of symptoms has been a major challenge to developing diagnostics and treatments. Should polygenic risk scores prove accurate, they could provide physicians with a list of their patients’ health risks well in advance, providing greater opportunity for early intervention.

Future Applications of Polygenic Risk Scores

In the January issue of the British Medical Journal (BMJ), researchers from UCSD outlined their development of a polygenic assessment tool to predict the age-of-onset of aggressive prostate cancer. As Dark Daily recently reported, for the first time in the UK, prostate cancer has surpassed breast cancer in numbers of deaths annually and nearly 40% of prostate cancer diagnoses occur in stages three and four. (See, “UK Study Finds Late Diagnosis of Prostate Cancer a Worrisome Trend for UK’s National Health Service,” May 23, 2018.)

An alternative to PSA-based testing, and the ability to differentiate aggressive and non-aggressive prostate cancer types, could improve outcomes and provide healthcare systems with better treatment options to reverse these trends.

While the value of polygenic scores should increase as algorithms and results are honed and verified, they also will most likely add to concerns raised about the impact genetic test results are having on patients, physicians, and genetic counselors.

And, as the genetic testing technology of personalized medicine matures, clinical laboratories will increasingly be required to protect and distribute much of the protected health information (PHI) they generate.

Nevertheless, when the data produced is analyzed and combined with other information—such as anatomic pathology testing results, personal/family health histories, and population health data—polygenic scores could isolate new biomarkers for research and offer big-picture insights into the causes of and potential treatments for a broad spectrum of chronic diseases.

—Jon Stone

Related Information:

Forecasts of Genetic Fate Just Got a Lot More Accurate

Polygenic Scores to Classify Cancer Risk

Association of Polygenic Risk Scores for Multiple Cancers in a Phenome-Wide Study: Results from the Michigan Genomics Initiative

Polygenic Risk Score May Identify Alzheimer’s Risk in Younger Populations

Use of an Alzheimer’s Disease Polygenic Risk Score to Identify Mild Cognitive Impairment in Adults in Their 50s

New Polygenic Hazard Score Predicts When Men Develop Prostate Cancer

Polygenic Hazard Score to Guide Screening for Aggressive Prostate Cancer: Development and Validation in Large Scale Cohorts

UK Study Finds Late Diagnosis of Prostate Cancer a Worrisome Trend for UK’s National Health Service