Team announces breakthrough for degenerative vision disorder

April 23, 2012

A research team, led by John Guy, M.D., professor of ophthalmology at Bascom Palmer Eye Institute of the University of Miami Miller School of Medicine, has pioneered a novel technological treatment for Leber Hereditary Optic Neuropathy (LHON), an inherited genetic defect that causes rapid, permanent, and bilateral loss of vision in people of all ages, but primarily males ages 20-40. Genetic mutations in the mitochondria (part of the cell that produces energy) cause the disorder. Currently, there is no cure for LHON.

However, Guy and his team have successfully modified a virus and used it to introduce healthy genes into the mitochondria to correct the . Using experimental models, they have proven that it is both safe and effective to replace mutated genes with healthy ones and that doing so prevents deterioration of the that form the optic nerve. This research demonstrates that when efficiently introduced into mitochondria, normal DNA can correct a biochemical defect in cellular energy production and restore visual function.

"A wide range of other factors, including aging, cancer, and Parkinson's disease, are also caused by mutations in the mitochondria," said Dr. Guy. "This new approach shows the vast potential for genetic-therapy applications, while helping to address a significant cause of blindness."

The healthy genes were delivered into the mitochondria via an innovative viral delivery system. Specifically, Guy redirected the adeno-associated virus (a small virus that infects humans but is not known to cause disease) to the mitochondria rather than to its typical target, the nucleus, where most genes are housed within the cell. He did so via a mitochondrial-targeting sequence (a peptide chain that directs the transport of a protein). This permitted the replacement of the defective mitochondrial gene with a healthy one, which then restored energy production to the affected ocular cells. Two National Institutes of Health/National Eye Institute grants, totaling $6.1 million funded this research, which began in 2007.

"Other research studies have shown that LHON patients who have lost their vision still have some sensitivity to light," said Guy. "This indicated that if you can restore the functioning of those cells through , those patients could see again." In conjunction with his research, Guy explored why only about 50 percent of patients with the genetic mutation develop LHON, while others do not.

Known for exploring gene therapy as a potential treatment for diseases of the , Guy holds several patents related to mitochondrial gene therapy biotechnology. His next steps will be to investigate incorporating all three genes that cause LHON into a single viral carrier and hopefully receive FDA approval to inject therapeutic genes into patients who have visual loss from mitochondrial disease.

On April 20, 2012, Proceedings of the National Academy of Sciences (PNAS) published an article by Guy about this recent breakthrough.

Explore further: Researchers study and develop approach to treat mitochondrial disorders

Related Stories

Researchers study and develop approach to treat mitochondrial disorders

April 3, 2012
(Medical Xpress) -- Within each of our cells are a number of organelles governing operations – making sure we function as smoothly as possible. But one slip on the molecular level could mean disaster.

Genetic map reveals clues to degenerative diseases

August 24, 2011
An international research team, spearheaded by Dr. Tim Mercer from The University of Queensland's Institute for Molecular Bioscience (IMB), has unlocked the blueprints to the ‘power plants' of the cell in an effort that ...

Why do neurons die in Parkinson's disease?

November 10, 2011
Current thinking about Parkinson's disease is that it's a disorder of mitochondria, the energy-producing organelles inside cells, causing neurons in the brain's substantia nigra to die or become impaired. A study from Children's ...

Study finds how to correct human mitochondrial mutations

March 12, 2012
Researchers at the UCLA stem cell center and the departments of chemistry and biochemistry and pathology and laboratory medicine have identified, for the first time, a generic way to correct mutations in human mitochondrial ...

Recommended for you

Researchers report startling glaucoma protein discovery

October 20, 2017
A discovery in a protein associated with glaucoma was so unheard of that for over two years, researchers ran it through a gauntlet of lab tests and published a new research paper on it. The tests validated what they initially ...

Curve-eye-ture: How to grow artificial corneas

October 19, 2017
Scientists at Newcastle University, UK, and the University of California have developed a new method to grow curved human corneas improving the quality and transparency - solely by controlling the behaviour of cells in a ...

Clinical study success for novel contact lens device aimed to improve glaucoma treatment

October 19, 2017
A novel contact lens device developed by University of Liverpool engineers to improve the treatment of glaucoma has been found to reliably track pressure changes in the eye and be wearable by people who took part in its first ...

Study indicates proof of concept for using a surrogate liquid biopsy to provide genetic profile of retinoblastoma tumors

October 12, 2017
Retinoblastoma is a tumor of the retina that generally affects children under 5 years of age. If not diagnosed early, retinoblastoma may result in loss of one or both eyes and can be fatal. Unlike most cancers that are diagnosed ...

Farsighted children struggle with attention, study finds

October 10, 2017
Farsighted preschoolers and kindergartners have a harder time paying attention and that could put them at risk of slipping behind in school, a new study suggests.

New drug reduces rate of progression of incurable eye disease

October 4, 2017
An international study including researchers from the Centre for Eye Research Australia (CERA) has found a way to slow the progression of dry age-related macular degeneration (AMD) - one of the most common causes of vision ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.