Medindia
Advertisement

Scientists Reverse Color Blindness in Monkeys Using Gene Therapy

by VR Sreeraman on September 17, 2009 at 2:41 PM

 Scientists Reverse Color Blindness in Monkeys Using Gene Therapy
Two monkeys were cured of color blindness thanks to gene therapy that one day may open the way to treating eye disorders in humans, scientists said on Wednesday.

The ground-breaking technique used a cold virus as a "Trojan horse" to infect cone-shaped cells in the retina, stealthily delivering a gene that provides a pigment which is sensitive to red.
Advertisement

About 20 weeks after the treatment, the two primates began to acquire full color vision, according to the paper, published by the British journal Nature.

"(...) We knew right away when it began to work," said Jay Neitz, a professor of ophthalmology at the University of Washington who led the work.
Advertisement

"It was as if they woke up and saw these new colours. The treated animals unquestionably responded to colours that had been invisible to them."

Color blindness is the inability to distinguish between different hues, particularly between red and green. Instead, these colours show up in shades of grey, causing problems for everyday tasks such as recognizing traffic lights.

Red-green color blindness is the commonest disease in humans that can be pinned to just a single mutation in the genetic code. It affects between five and eight percent of males and around one percent of women, according to various figures.

The experiment was carried out on two adult squirrel monkeys (Saimiri sciureus).

One was called Dalton -- named after the 18th-century British scientist, John Dalton, who discovered color blindness -- and the other Sam. Both had been color-blind since birth.

For more than a year, the monkeys were given an adapted form of a standard vision-testing technique to find out exactly which out of 16 hues they failed to see.

When the monkeys traced a color pattern on a computer touch screen, they were given a reward of grape juice.

The researchers then inserted a human gene called L-opsin into a disabled cold virus and delivered it to the monkeys' retina through several injections.

The gene colonised cone cells, the most important vision receptors in mammals, adding the missing light-sensitive pigment.

Color vision in Sam and Dalton has remained stable more than two years after treatment, the paper says.

It is the first time that a vision disorder has been corrected in primates in which all photo-receptors are intact and healthy.

It thus gives the lie to the belief that congenital vision defects become "hard-wired" through neural connections soon after birth and cannot be corrected.

"Although color blindness is only moderately life-altering, we've shown we can cure a cone disease in a primate, and that it can be done safely," said co-researcher William Hauswirth, a professor of ophthalmic molecular genetics at the University of Florida.

"That's extremely encouraging for the development of therapies for human cone diseases that really are blinding," he said in a press release.

Targeting cone cells could potentially cure common types of blindness such as age-related macular degeneration and diabetic retinopathy.

Gene medicine is one of the most alluring areas of biotechnology, as it holds out the promise of blocking or reversing inherited disease. But this new frontier has also been blighted by occasional setbacks, such as an unexpected and uncontrollable response from the immune system.

Source: AFP
LIN
Advertisement

Advertisement
News A-Z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
News Category
What's New on Medindia
Lower Respiratory Tract Infections Linked to Obstructive Sleep Apnea in Children
Type 2 Diabetes can be Controlled by Unripen Green Jackfruit Flour
Covid Pandemic: How Parents can Help Kids Deal with Back-to-School Anxiety
View all

Medindia Newsletters Subscribe to our Free Newsletters!
Terms & Conditions and Privacy Policy.

More News on:
DNA Finger Printing Reiki and Pranic Healing Pancreas Blindness Facts Colors and Moods Best Disease Usher Syndrome Color Blindness Trachoma 
Recommended Reading
Best Disease
People with Best disease may be completely normal or may suffer from blindness in due course....
Color Blindness
Color blindness is a visual disorder of perceiving parts of the color spectrum. Color blindness test...
Colors and Moods
Study of the psychology of color, technically termed as chromology delves into the influence of colo...
DNA Finger Printing
DNA fingerprinting is a technique which helps forensic scientists and legal experts solve crimes, id...
Trachoma
Trachoma is a bacterial eye infection. It is the main cause of irreversible blindness due to infecti...
Usher Syndrome
Usher syndrome is a rare genetic disease which is the leading cause of deaf-blindness in humans....

Disclaimer - All information and content on this site are for information and educational purposes only. The information should not be used for either diagnosis or treatment or both for any health related problem or disease. Always seek the advice of a qualified physician for medical diagnosis and treatment. Full Disclaimer

© All Rights Reserved 1997 - 2021

This site uses cookies to deliver our services. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Use