WASHINGTON
(AP)—Gene scans for everyone? Not so fast. New research suggests that
for the average person, decoding your own DNA may not turn out to be a
really useful crystal ball for future health.
Today,
scientists map entire genomes mostly for research, as they study which
genetic mutations play a role in different diseases. Or they use it to
try to diagnose mystery illnesses that plague families. It’s different
from getting a genetic test to see if you carry, say, a particular
cancer-causing gene.
But
as genome mapping gets faster and cheaper, scientists and consumers
have wondered about possible broader use: Would finding all the glitches
hidden in your DNA predict which diseases you’ll face decades later?
Johns
Hopkins University developed a model using registries of thousands of
identical twins, who despite their shared genes can develop different
diseases. They examined 24 ailments, including different types of
cancer, heart disease, diabetes and Alzheimer’s.
Under
best-case scenarios, most people would be told they had a somewhat
increased risk of at least one disease, said Dr. Bert Vogelstein, a
Hopkins cancer geneticist and the study’s senior author.
But
a negative test for most of the rest of the diseases doesn’t mean you
won’t get them. It just means that you’re at no more risk than the
general population. Those are the findings Vogelstein’s team reported
Monday in the journal Science Translational Medicine. Why? Cancer, for
example, typically doesn’t result from inherited genes but from
mutations that can form anytime, Vogelstein explained. Many other common
diseases are influenced by lifestyle and environment—so you’d still
have to eat well, exercise and take the other usual precautions.
The study examined just one possible future use of genome mapping. It doesn’t mean there aren’t other benefits from the effort.
Make
no mistake: This technology does have huge promise for customizing care
for certain people, especially children with otherwise undiagnosed
illnesses, said Dr. James Lupski of Baylor College of Medicine, who
wasn’t involved in Monday’s study.
Last
year, Baylor researchers reported one of the first examples of genome
mapping directly benefiting a patient. It found a mutation that pointed
to the right treatment for a 14-year-old girl’s baffling trouble
breathing.
But
even if finding a genetic explanation doesn’t lead to treatment,
knowing whether it was inherited can help parents decide whether to
chance having another baby, Lupski added.
“There
are families where this can be transformative,” said Lupski. He had his
own genome mapped to identify the cause of a rare nerve disorder.
Source: The Associated Press
