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Researchers identify gene in age-related
Hearing
Loss
Newswise — Presbycusis, or age-related
hearing loss, accounts for 30 percent of all
hearing loss. So, why do some people lose
their hearing as they get older but other
people can still hear a pin drop?
The answer may be in a study released online
in the journal Human Molecular Genetics.
“This is the first ever and largest
genome-wide association study for
age-related hearing loss,” said Rick
Friedman, M.D., Ph.D., lead author and House
Ear Institute principal investigator and
surgeon at the House Clinic.
The study was conducted in collaboration
with colleagues at the Phoenix-based
Translational Genomics Research Institute (TGen),
Affymetrix in Santa Clara, Calif., and the
University of Antwerp, Belgium.
It uncovered several genes, but one gene
stands out and is believed to put people at
risk for hearing loss as they age.
They discovered a common variant in the GRM7
gene, which the research team believes may
be associated with susceptibility to
glutamate excitotoxicity and hearing loss.
It is the overexpression of glutamate that
causes damage to the inner and outer hair
cells in the inner ear leading to
age-related hearing loss.
“Finding the genetic causes of age-related
hearing loss could lead to treatments that
would bring relief to millions of people
worldwide who now suffer from social
isolation, depression and even cognitive
impairment as a result of not being able to
properly understand what others are
saying,’’ said Dr. Matthew Huentelman, an
investigator in TGen’s Neurogenomics
Division and one of the lead authors.
Researchers believe this paper’s findings
represent important and significant progress
in the efforts to discover the origins of
presbycusis.
“We have known for a long time that genes
play an important role in presbycusis, but
until now genetic research has lagged behind
compared to other important diseases,” said
Guy Van Camp, director of the Hereditary
Deafness Laboratory and professor,
University of Antwerp, Belgium.
“The
identification of GRM7 is a very exciting
result, as it may provide insights in the
development of the disease.”
The study participants were Caucasian, ages
53 to 67, and the samples were collected at
eight centers in six nations throughout
Europe from population registries or
audiological consultations.
The team of investigators analyzed the
samples and identified genetic risks.
In the lab, the research team used
Affymetrix GeneChip® Human Mapping 500K to
score markers across the entire genome of
more than 2,000 samples.
Friedman said the next step is developing a
laboratory model to test pharmaceuticals for
possible treatment of presbycusis in the
future.
For more information, please visit the
institute web site,
http://www.hei.org.
About House Ear
Institute
The House Ear Institute (HEI) is a
non-profit 501(c)(3) organization dedicated
to advancing hearing science through
research and education to improve quality of
life.
HEI scientists investigate the cellular and
molecular causes of hearing loss and related
auditory disorders as well as neurological
processes pertaining to the human auditory
system and the brain.
Our researchers also explore technology
advancements to improve auditory implants,
hearing aids, diagnostic techniques and
rehabilitation tools.
The Institute shares its knowledge with the
scientific and medical communities as well
as the general public through its education
and outreach programs. For more information
about HEI please call (800) 388-8612 or
visit
http://www.hei.org.
About TGen
The Translational Genomics Research
Institute (TGen) is a non-profit
organization dedicated to conducting
groundbreaking research with life changing
results.
Research at TGen is focused on helping
patients with diseases such as cancer,
neurological disorders and diabetes. TGen is
on the cutting edge of translational
research where investigators are able to
unravel the genetic components of common and
complex diseases. Working with collaborators
in the scientific and medical communities,
TGen believes it can make a substantial
contribution to the efficiency and
effectiveness of the translational process.
For more information, visit:
http://www.tgen.org.
About the Hereditary Deafness Laboratory,
University of Antwerp, Belgium
This research group, headed by Prof. Guy Van
Camp, has localized and identified many
genes for different forms of hereditary
deafness over the last 15 years.
Most of this work was based on purely
genetic forms of deafness. Over the last
couple of years, this laboratory has started
with the analysis of complex forms of
hearing impairment such as presbycusis and
noise-induced hearing impairment.
These types of hearing impairment are caused
by a complex interplay between environmental
factors, such as noise or exposure to toxic
substances or medication, and genes that
make people susceptible.
The laboratory has collected large numbers
of samples, and has developed new
methodologies for the analysis of these
diseases.
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