Featured Research

from universities, journals, and other organizations

Mice Show Function Of Gene That Causes Two Types Of Blindess

Date:
July 14, 1999
Source:
University Of Texas Southwestern Medical Center At Dallas
Summary:
UT Southwestern Medical Center at Dallas scientists have used genetically altered mice to help explain two types of human blindness, one that occurs in children and another that develops in approximately one in four adults over 65.

DALLAS - July 9, 1999 - UT Southwestern Medical Center at Dallas scientists have used genetically altered mice to help explain two types of human blindness, one that occurs in children and another that develops in approximately one in four adults over 65.

Stargardt's disease affects about one in 20,000 children over age 6, and age-related macular degeneration (AMD) develops in approximately one in four adults over 65. Both disorders affect central vision, which enables reading, driving and face recognition. The work is a major step toward finding treatment for these macular-degenerative illnesses, in which cells in the center of the retina -- the macula -- die.

The research, published in today's issue of Cell, describes a UT Southwestern study of mice that the investigators developed by inactivating the ABCR gene, which produces Rim protein (RmP). This study identifies the molecule transported by RmP in the retina's photoreceptor cells. When a mutation occurs in ABCR, then RmP dysfunctions and cannot perform its transporter role.

"Our research revealed, among other things, the biochemical change in patients with Stargardt's that makes vision more difficult when coming from sunshine into a dimly lit room," said Dr. Gabriel Travis, associate professor of psychiatry and an investigator in the Center for Basic Neuroscience at UT Southwestern. This symptom is called delayed dark adaptation, an early sign of the illness, which is the most common form of juvenile macular degeneration.

Because the genetically engineered animals lack the ABCR gene, RmP also is missing. In normal mice, RmP inhibits accumulation in the retinal pigment epithelium (RPE) of lipofuscin, a brown pigment generally associated with aging. The buildup of lipofuscin poisons the RPE, which then cannot perform its role of keeping photoreceptor cells healthy. The unhealthy cells begin to die, causing blindness. The lipofuscin accumulation seen in the rodents is identical to what is observed in humans with Stargardt's and AMD.

"Although the mouse retina does not contain a macula, our studies offer a possible explanation for vulnerability of the macula in several human blinding diseases," Travis said. "We observed complete inhibition of lipofuscin accumulation when mutant rodents were raised in total darkness. This observation suggests that patients with Stargardt's disease and some forms of AMD could slow the progression of their blindness by wearing sunglasses and avoiding bright light."

If researchers can discover methods to inhibit lipofuscin accumulation in retinal pigment epithelial cells, new treatments for Stargardt's disease and AMD may be possible. Currently no treatments or cures are available for Stargardt's, and only a small percentage of AMD cases can be treated with lasers. Once a patient is diagnosed with Stargardt's, there is rapid progression to legal blindness.

Other researchers involved in this study were Dr. Jian Weng, assistant professor of psychiatry; Dr. Nathan Mata, a postdoctoral fellow in psychiatry; Dr. Sassan Azarian, instructor of psychiatry; and Dr. David Birch and Radouil Tzekov of the Retina Foundation of the Southwest, Dallas. Birch is a UT Southwestern adjunct professor of ophthalmology.

The National Eye Institute and the Foundation Fighting Blindness funded the work.


Story Source:

The above story is based on materials provided by University Of Texas Southwestern Medical Center At Dallas. Note: Materials may be edited for content and length.


Cite This Page:

University Of Texas Southwestern Medical Center At Dallas. "Mice Show Function Of Gene That Causes Two Types Of Blindess." ScienceDaily. ScienceDaily, 14 July 1999. <www.sciencedaily.com/releases/1999/07/990714073150.htm>.
University Of Texas Southwestern Medical Center At Dallas. (1999, July 14). Mice Show Function Of Gene That Causes Two Types Of Blindess. ScienceDaily. Retrieved August 20, 2014 from www.sciencedaily.com/releases/1999/07/990714073150.htm
University Of Texas Southwestern Medical Center At Dallas. "Mice Show Function Of Gene That Causes Two Types Of Blindess." ScienceDaily. www.sciencedaily.com/releases/1999/07/990714073150.htm (accessed August 20, 2014).

Share This




More Health & Medicine News

Wednesday, August 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Possible Ebola Patient in Isolation at California Hospital

Possible Ebola Patient in Isolation at California Hospital

Reuters - US Online Video (Aug. 20, 2014) — A patient who may have been exposed to the Ebola virus is in isolation at the Kaiser Permanente South Sacramento Medical Center. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Raw: World's Oldest Man Lives in Japan

Raw: World's Oldest Man Lives in Japan

AP (Aug. 20, 2014) — A 111-year-old Japanese was certified as the world's oldest man by Guinness World Records on Wednesday. Sakari Momoi, a native of Fukushima in northern Japan, was given a certificate at a hospital in Tokyo. (Aug. 20) Video provided by AP
Powered by NewsLook.com
Do More Wedding Guests Make A Happier Marriage?

Do More Wedding Guests Make A Happier Marriage?

Newsy (Aug. 20, 2014) — A new study found couples who had at least 150 guests at their weddings were more likely to report being happy in their marriages. Video provided by Newsy
Powered by NewsLook.com
Ebola-Hit Sierra Leone's Freetown a City on Edge

Ebola-Hit Sierra Leone's Freetown a City on Edge

AFP (Aug. 19, 2014) — Residents of Sierra Leone's capital voice their fears as the Ebola virus sweeps through west Africa. Duration: 00:56 Video provided by AFP
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