Scientists have created a strong new tool to calculate a
person’s inherited risks for a heart condition, carcinoma, and three other
serious conditions.
By surveying changes in DNA at 6.6 million places within
the human genome, investigators at the Broad Institute and Harvard University
we're ready to identify more people in danger than do the standard genetic
tests, which take into consideration only a few genes.
Of 100 attack patients, for instance, the quality methods
will identify two who have one mutation that places them at increased risk.
But
the new tool will find 20 of them, the scientists reported on Monday within the
journal Nature Genetics.
The researchers are now building an internet site that will
allow anyone to upload genetic data from a corporation like 23andMe or
Ancestry.com.
Users will receive risk scores for a heart condition, carcinoma,
Type 2 diabetes, chronic inflammatory bowel disease, and fibrillation.
People won't be charged for his or her scores.
A risk score, including obtaining the genetic data, should
cost but $100, said Dr. Daniel Rader, a professor of molecular medicine at The University of Pennsylvania.
Dr. Rader, who wasn't involved in the study, said the university
will soon offer such a test to patients to assess their risk for a heart
condition. For now, the university won't charge for it.
Dr. Sekar Kathiresan, the senior author of the new paper
and director of the middle for Genomic Medicine at Massachusetts General The hospital said his team had validated the guts risk calculation in multiple
populations.
But DNA isn't destiny, Dr. Kathiresan stressed.
A healthy
lifestyle and cholesterol-lowering medications can substantially reduce the
risk of attack, even in those that have inherited a genetic predisposition.
The new tool can also find people at the low end of the
danger range for the five diseases.
This could prove useful to certain
patients: for instance, a lady who is trying to make a decision when she should
start having regular mammograms, or a 40-year-old man with a rather high
cholesterol level who wants to understand if he should take a statin.
Still, there are concerns about how the genetic test is
going to be used. “It carries great hope, but also comes with tons of
questions,” said Dr. David J. Maron, director of preventive cardiology at
Stanford University.
“Who should get tested? How should the results be provided?
Physicians aren't generally well trained to supply genetic test results.”
And, he wondered, will the results actually lead people to
form decisions that improve their health?
People may have guidance before and after getting these
kinds of risk scores, noted Eric Schadt, dean of precision medicine at the
Icahn School of Drugs at Sinai.
Patients might not appreciate the results of learning they
need a high likelihood of getting an attack or carcinoma or one among the
opposite diseases the test assesses.
“Do people really understand that when you learn something
you can't unlearn it?” said Dr. Schadt, who is additionally chief executive of
Sema4, a diagnostics company.
But doctors said this type of risk assessment is that the wave of the longer term.
“I’m unsure we will stop it,” said Dr. John Mandrola,
a cardiac electrophysiologist at Baptist Health in Louisville, Ky.
The study began because there was general agreement among
researchers that a lot of common diseases are linked to not one mutation, but
rather to thousands or many mutations, said the primary author of the new
paper, Dr. Amit V. Khera, a cardiologist at Massachusetts General Hospital and
a researcher at the Broad Institute.
In recent years, scientists have cataloged quite 6 million
tiny changes in DNA that slightly affect the probabilities that folks will get
various diseases.
Each of these genetic alterations has such a little effect
— a 1 percent approximately increase or decrease during a person’s odds of
getting a disease — that it might not be helpful to check for everyone in
isolation.
But it should be possible, scientists felt, to mix data on
all the tiny DNA changes to construct a private risk score.
To try to that, the
researchers needed a replacement algorithm that might weigh the importance of
the variations within the genes.
Then that they had to check the danger scores they
obtained. Dr. Khera and his colleagues turned to the U.K. Biobank, which holds
genetic and disease information on half 1,000,000 people.
The investigators found that their algorithm did predict
the chances of being diagnosed with one of the five diseases. But the U.K.
Biobank consists mostly of white Europeans.
So the investigators also tested and validated their method
in populations of East Asians, South Asians, African Americans, and Hispanics.
The researchers also tried their algorithm on 20,000
patients who were seen at Brigham and Women’s Hospital and Massachusetts
General Hospital.
They found that those that had a high-risk score for an attack was indeed fourfold more likely to possess had an attack than other
patients.
“Unless I do that genetic testing, there's no way I could
pick those people out,” Dr. Khera said.
Just as important is finding people at very low risk, he
and other researchers said.
Clues to Your Health Are Hidden at 6.6 Million Spots in Your DNA
Scientists have created a strong new tool to calculate a
person’s inherited risks for a heart condition, carcinoma, and three other serious
conditions.
By surveying changes in DNA at 6.6 million places within
the human genome, investigators at the Broad Institute and Harvard University
we're ready to identify more people in danger than do the standard genetic
tests, which take into consideration only a few genes.
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