Featured Research

from universities, journals, and other organizations

Genetic Hearing Loss May Be Reversible Without Gene Therapy

Date:
February 23, 2007
Source:
Emory University
Summary:
A large proportion of genetically caused deafness in humans may be reversible by compensating for a missing protein. Researchers have found that in mice, increasing the amount of the protein connexin26 in the ear's cochlea compensates for an absence of another protein, connexin30. The findings come 10 years after scientists first discovered that connexin26 mutations cause much of the deafness diagnosed at birth.

A large proportion of genetically caused deafness in humans may be reversible by compensating for a missing protein, based on discoveries in mice.

Emory University researchers have found that in mice, increasing the amount of the protein connexin26 in the ear's cochlea compensates for an absence of another protein, connexin30. The findings come 10 years after scientists first discovered that connexin26 mutations cause much of the deafness diagnosed at birth.

Xi (Erick) Lin, PhD, associate professor of otolaryngology and cell biology at Emory University School of Medicine, was lead author of the study, published recently in the Proceedings of the National Academy of Sciences.

"There are millions of deaf people affected by mutations in this one gene, connexin26," he says. "Congenital hearing loss is one of the most common human genetic birth defects, and that is why in almost all the states universal newborn hearing screening is mandated by law [including Georgia]."

In people without congenital hearing loss, connexin26 and connexin30 work together to form the cochlea's hybrid junction gaps, which facilitate intercellular communication. But when one of the proteins is missing, the hybrid junction gaps fail to work, and the cochlea's hair cells die off, leaving the body incapable of translating sounds into nerve impulses.

Even though scientists knew connexin26 was implicated in congenital deafness, they did not know precisely why. Working with Emory colleagues and scientists from the University of Bonn in Germany, Dr. Lin developed contrasting hypotheses.

"The deafness could have two very different explanations," he says. "Either hybrid gap junctions have special biophysical properties that cannot be replaced by gap junctions built with only one type of connexin, or mutations in one of the two connexins just cut the supply for making the gap junctions in half."

By adding extra connexin26 to mice that were missing connexin30, Dr. Lin and his team proved the latter hypothesis. With the additional connexin26, hearing sensitivity was restored and the expected hair cell death never occurred. Those positive findings led Dr. Lin to conclude, "The problem is simply caused by not having enough protein remaining in the ear of these mutant mice to assemble gap junctions."

Dr. Lin and his colleagues are now working to see if connexin-related deafness can be reversed in a mouse model, or if increasing connexin30 may help when connexin26 is absent.

As the research picks up momentum, these results--and future findings--may mean big changes for how congenital deafness is approached. Up to now, says Dr. Lin, scientists working on hearing loss had placed all their bets on gene therapy. That may no longer make sense. "Gene therapy, which has very few successful cases so far, may not be necessary," explains Dr. Lin.

Instead, Dr. Lin's findings indicate that a drug to boost connexin26 may be all that is needed. "Our work predicts that a drug should be sufficient to cure connexin30 deletion-caused deafness," he says.

The study was funded by the National Institute on Deafness, the Woodruff Foundation, the Deafness Research Foundation and the National Organization for Hearing Research.


Story Source:

The above story is based on materials provided by Emory University. Note: Materials may be edited for content and length.


Cite This Page:

Emory University. "Genetic Hearing Loss May Be Reversible Without Gene Therapy." ScienceDaily. ScienceDaily, 23 February 2007. <www.sciencedaily.com/releases/2007/02/070222155400.htm>.
Emory University. (2007, February 23). Genetic Hearing Loss May Be Reversible Without Gene Therapy. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2007/02/070222155400.htm
Emory University. "Genetic Hearing Loss May Be Reversible Without Gene Therapy." ScienceDaily. www.sciencedaily.com/releases/2007/02/070222155400.htm (accessed April 20, 2014).

Share This



More Mind & Brain News

Sunday, April 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Study On Artists' Brain Shows They're 'Structurally Unique'

Study On Artists' Brain Shows They're 'Structurally Unique'

Newsy (Apr. 17, 2014) The brains of artists aren't really left-brain or right-brain, but rather have extra neural matter in visual and motor control areas. Video provided by Newsy
Powered by NewsLook.com
Is Apathy A Sign Of A Shrinking Brain?

Is Apathy A Sign Of A Shrinking Brain?

Newsy (Apr. 17, 2014) A recent study links apathetic feelings to a smaller brain. Researchers say the results indicate a need for apathy screening for at-risk seniors. Video provided by Newsy
Powered by NewsLook.com
Are School Dress Codes Too Strict?

Are School Dress Codes Too Strict?

AP (Apr. 16, 2014) Pushing the limits on style and self-expression is a rite of passage for teens and even younger kids. How far should schools go with their dress codes? The courts have sided with schools in an era when school safety is paramount. (April 16) Video provided by AP
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins