Gene therapy effective against form of inherited vision loss

Some vision was returned to mice with Leber hereditary optic neuropathy after being injected with a normal version of the gene that causes it.

By Stephen Feller

MIAMI, Oct. 6 (UPI) -- Researchers developed a method to deliver a genetic therapy for Leber hereditary optic neuropathy, or LHON, finding it improved vision in mice bred to have the degenerative condition.

The inherited condition, caused by a mutation of the ND4 gene, often starts with blurring and clouding of vision and progresses with a loss of sharpness and color vision due to the death of nerve cells in the eye that relay visual information to the brain. The condition generally affects central vision, which is needed for tasks such as driving, reading, and seeing faces.


LHON, like other diseases caused by DNA mutations in the mitochondria, has been difficult to treat. The early success of the experimental therapy with mice, however, may help lead to therapies for similar diseases.

"This study marks an important contribution to research on LHON, and in efforts toward an effective therapy," said Dr. Maryann Redford, a program director at the National Eye Institute, in a press release. "But the implications are even broader, because the approaches that the investigators used could aid therapy development for a vast array of other mitochondrial diseases."


Viruses are one of the central ways genes are delivered to cells but have trouble penetrating mitochondria. In order to overcome this, researchers attached a cellular protein mitochondria need but do not make onto the virus carrying a damaged version of ND4. This virus was then injected into fertilized mouse cell eggs and, over several generations, the researchers had mice with LHON.

A normal ND4 gene was then added to the virus and injected into to the eye, leading to improved vision in the affected mice. For mice who did not have the genetic mutation, the ND4-carrying virus had no effect on vision.

The study is published in the Proceedings of the National Academy of Sciences.

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