Gene therapy first to "stop" the most common cause of blindness

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Fergus Walsh

An Oxford woman has become the first person in the world to benefit from gene therapy in an attempt to put an end to the most prevalent form of blindness in the Western world.

Surgeons have injected a synthetic gene behind Janet Osborne's eye to prevent the death of more cells.

It is the first treatment to target the underlying genetic cause of age-related macular degeneration (AMD).

In the UK, approximately 600,000 people are affected by AMD, most of whom have severe vision impairment.

Janet Osborne told BBC News: "I find it difficult to recognize faces with my left eye because my central vision is blurry, so if this treatment could stop it from getting worse, it would be amazing."

The treatment was performed under local anesthesia last month at the Oxford Eye Hospital by Robert MacLaren, professor of ophthalmology at Oxford University.

He told the BBC: "Genetic therapy administered early to preserve the vision of patients who lose their sight would be a great advance in ophthalmology and certainly what I hope to see in the near future."

Osborne, age 80, is the first of 10 AMD patients participating in a gene therapy therapy trial, made by Gyroscope Therapeutics, funded by Syncona, the investment company founded by Wellcome Trust.

What is AMD?

The macula is part of the retina and is responsible for the central vision and the finer details.

In age-related macular degeneration, retinal cells die and are not renewed.

The risk of developing AMD increases with age.

Most people affected, including those in this trial, have what is known as dry AMD, where vision loss is progressive and can take many years.

Wet AMD can develop suddenly and cause rapid vision loss, but can be treated if it is detected quickly.

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Fergus Walsh

How does gene therapy work?

As some people get older, the genes responsible for the natural defenses of the eye begin to malfunction and begin to destroy the cells of the macula, resulting in vision loss.

An injection at the back of the eye releases a harmless virus containing a synthetic gene.

The virus infects retinal cells and releases the gene.

This allows the eye to make a protein designed to prevent cells from dying and thus keep the macula healthy.

The early-stage trial, at Oxford Eye Hospital, is aimed primarily at verifying the safety of the procedure. It is underway in patients who have already lost some of their vision.

If successful, the goal would be to treat patients before they lose their sight, with the goal of stopping AMD.

This would have major consequences for the quality of life of patients.

It is too early to know if Ms. Osborne's vision loss to her left eye has been stopped, but the vision of everyone involved in the trial will be monitored.

At home, she told BBC News: "I always love gardening with my husband, Nick, who grows a lot of vegetables.

"If I could continue to peel and cut the vegetables, and keep my current level of independence, it would be absolutely wonderful."

There is already a successful gene therapy treatment for another rare eye disorder.

In 2016, the same team at Oxford showed that a single injection could improve the vision of patients with choroideremia, who would otherwise have become blind.

And last year, doctors at London's Moorfields Eye Hospital restored the sight of two patients with AMD by implanting a patch of stem cells on the damaged area at the back of the eye.

It is hoped that stem cell therapy could help many people who have already lost their sight.

But the Oxford test is different because it aims to address the underlying genetic cause of AMD and could be effective in curbing the disease before people become ill. blind.

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