A 58-year-old man blinded by a degenerative genetic disease was able to partially recover his sight thanks to an innovative technique combining gene therapy and light stimulation.

This is the first time that this technique, called optogenetics, has made it possible to obtain partial recovery of visual function, say the researchers behind this clinical trial, which involved French, Swiss and American teams.

The patient in the study has retinopathy pigmentosa, a degenerative genetic disease of the eye that destroys photoreceptor cells in the retina, leading to progressive loss of vision that usually progresses to blindness.

While he could only perceive the presence of light, the therapy now allows him to locate and touch objects, according to the study, published Monday in the journal Nature Medicine.

Large notebook, small box

In normal vision, photoreceptors in the retina use proteins capable of reacting to light energy, opsins, which deliver visual information to the brain via the optic nerve. In order to restore sensitivity to light, the patient was injected with the gene encoding one of these proteins, called ChrimsonR, which detects amber light, the study describes.

Nearly five months after receiving the injection, to give his body time to produce this protein in sufficient quantity, he performed various exercises, equipped with dedicated glasses fitted with a camera;

In a first test consisting of perceiving, locating and touching a large notebook and a small box of staples, he managed to touch the notebook in 92% of the cases but could only grasp the box in 36% of the tests.

One in 3,500 people 

“If optogenetics, a technique that has already existed for twenty years, has revolutionized fundamental research in neuroscience (...), this is the first time internationally that this innovative approach has been used in humans and that its clinical benefits have been demonstrated, ”underline the Institut de la Vision (Sorbonne University / Inserm / CNRS) and the Quinze-Vingts hospital in Paris, which conducted the clinical trial in association with the University of Pittsburgh (United States). United), the Basel Institute of Molecular and Clinical Ophthalmology (Switzerland), the company Streetlab and the French biotech GenSight Biologics.

Retinopathy or retinitis pigmentosa affects one in 3,500 people, according to the European Orphanet database, and can begin at any age, with a greater frequency of occurrence between 10 and 30 years.

The genes responsible are very numerous, but certain mutations are frequently found in people with the disease.

"Blind people with different types of neurodegenerative diseases of photoreceptors" but retaining "a functional optic nerve" will be "potentially eligible for treatment, explains Professor José-Alain Sahel, founder in 2009 of the Institute of vision, dedicated at retinal diseases.

"But it will take time before this therapy can be offered."

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  • Genetic diseases

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  • Blinded

  • Genetic