Operation saves eyesight in children with rare condition

Medics in the UK have become the first in the world to successfully administer a pioneering gene therapy that preserves sight in young children with an extremely rare genetic condition that usually causes blindness in the first few years of life.

- STORM NEWTON

The patients, who were essentially blind at birth, can now see shapes, find toys, recognise faces, and in some cases, can even read and write. The procedure, which takes around an hour, involves injecting healthy copies of the affected gene into the back of one eye to “kick start” sensitivity.

The condition is so rare that the first children to have the therapy were selected from overseas. Specialists hope it can be made more widely available in the UK and elsewhere as a licensed treatment.

Four children were selected for the gene therapy by specialists from Moorfields Eye Hospital and UCL Institute of Ophthalmology in 2020.

All had severe retinal dystrophy known as leber congenital amaurosis (LCA), an inherited condition that causes vision loss due to a defect in the AIPL1 gene.

This gene is important for the function of photoreceptors, lightsensing cells in the retina that convert light into electrical signals that the brain interprets as vision.

Professor James Bainbridge, consultant retinal surgeon at Moorfields Eye Hospital and professor of retinal studies at UCL Institute of Ophthalmology, said: “Typically, they can only distinguish light and dark, and that little sight they will lose within the first few years of life.

“So what we found is that by providing the gene to their eyes that’s otherwise lacking, we can substantially improve their sight, and this appears to have a positive impact on their general development.”

The operations were carried out at Great Ormond Street Hospital in London, with medics performing keyhole surgery on patients aged between one and two to access the eye.

Healthy copies of the AIPL1 gene, contained in a harmless virus, were then injected into the retina, the light-sensitive layer of tissue at the back of the eye.