DNA sweep finds new genes linked to diabetes
Sun Jan 17, 12:14 pm ET
Hundreds of scientists sifting through genetic data from
122,000 people have quintupled the number of gene variants known to
boost the risk of diabetes, a pair of studies released Sunday reported.
A consortium of researchers first isolated 10 gene mutations that help
determine the body's ability to regulate blood sugar and insulin
levels, the key factors underlying type 2 diabetes.
In a companion study, the same consortium -- pooling the resources of
more than 100 institutions in Europe, the United States, Canada and
Australia -- determined that two of these newly-identified variants
directly influenced the risk of diabetes.
It also fingered an additional three genetic culprits that had already been
linked to changes in glucose levels.
"Only four gene variants had previously been associated with glucose
metabolism, and just one of them was known to affect type 2 diabetes," said
Jose Florez, a researcher at Massachusetts General Hospital and co-lead author
of one of the studies.
"Finding these new pathways can help us better understand how glucose
is regulated, distinguish between normal and pathological glucose
variations, and develop potential new therapies," he said in a
statement.
One gene in particular, known as GIPR-A, was found to play a prominent role.
Usually, GIPR-A produces a protein that is part of the normal hormone
response to eating, stimulating the release of insulin to control sugar
levels in the blood.
The mutated version, however, impairs this response, resulted in elevated
glucose.
Diabetes occurs when our bodies fail to produce sufficient insulin or
when our cells fail to recognise and react to the insulin produced,
resulting in abnormally high blood sugar levels.
The MAGIC -- Meta-Analysis of Glucose and Insulin-related traits Consortium --
investigators noted that other genetic factors related to diabetes remain to be
found.
"We've still only identified about 10 percent of the genetic
contribution to glucose levels in nondiabetic individuals, so we need
to investigate the impact of other possibly more complex or rare forms
of gene variation, along with the role of gene-environment interaction,
in causing type 2 diabetes," said Florez.
Diabetes is closely linked to lifestyle, especially the kinds and quantity of
food we consume.
More than 220 million people worldwide are afflicted with the disease,
which kills more than one million people every year, according to the
World Health Organization (WHO).
As obesity rates increase, the number of deaths could double between 2005 and
2020, the WHO has said.
Both studies were published online in the journal Nature Genetics.
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