CONTACT: JENNIFER CRONIN
2130 Medical Laboratories
Iowa City IA 52242
(319) 335-5661; fax (319) 335-9917
Release: July 7, 1999
UI researchers show prominence of gene mutation that
causes inherited deafness
IOWA CITY, Iowa One in 33 normal hearing people
in the Midwest has a mutated gene that causes inherited deafness, according
to recent University of Iowa Health Care research findings.
The mutated gene known as GJB2, which can be passed
on from parent to offspring, is thought to be the leading cause of childhood
deafness. Although having the mutation does not necessarily mean that the
individual will be born deaf, UI researchers showed that 35 percent of their
52 study subjects who were deaf had the mutated gene.
The UI study helps make it possible for families with
children who are born with severe hearing impairments or total deafness to
know the reason for the condition. This genetic test eliminates the need for
other more dangerous and less effective diagnostic tests.
"This is significant," said Glenn Green,
M.D., UI research fellow in otolaryngology and lead researcher in the UI investigation.
"If you dont know the cause, its hard to know how best to
rehabilitate the patient."
Based on their work, Green and his colleagues know
that cochlear implants work especially well on patients with the GJB2 mutation.
However, the UI investigators plan to look at other strategies to find out
if there is an even better way of treating these individuals. Cochlear implants
are electronic devices that a physician surgically places in a person's cochlea.
The device, which receives signals from a processor worn outside the body,
takes the place of damaged or absent cochlear hair cells. The device converts
acoustic information into electrical signals that can be transmitted to the
brain and perceived as sound.
In addition to evaluating treatments, the UI researchers
plan to start looking at other genes that may lead to deafness as well as
develop more precise tests for detecting severe-to-profound deafness due to
About one in every 1,000 children is born with severe
hearing impairment or total deafness. For some time, researchers have suspected
that the deafness was genetic, but there had not been any focus on identifying
the exact problem until relatively recently. The UI conclusions are consistent
with evidence from France and Australia.
An article on the UI findings concerning GJB2 mutation
appeared in a recent issue of the Journal of the American Medical Association.
The work was supported by grants from the National Institute on Deafness and
Other Communications Disorders, and the National Center for Human Genome Research.