"Extremely impressive results": children regain sight thanks to gene therapy

British doctors have managed to cure blindness in children born with a rare disease using a new gene therapy, the Guardian reports.

The child patients had Leber congenital amaurosis (LCA), a severe form of retinal dystrophy that causes vision loss due to a defect in the AIPL1 gene. Those affected are legally declared blind from birth.

But four children with the genetic condition can now see shapes, find toys, recognize their parents' faces and, in some cases, even read and write. It was made possible by doctors who injected healthy copies of the AIPL1 gene into their eyes during surgery that lasted just an hour.

"The results for these children are extremely impressive and show the power of gene therapy to change lives," said Professor Michel Michaelides, consultant retina specialist at Moorfields Eye Hospital and professor of ophthalmology at the Institute of Ophthalmology at UCL (University College London).

For the professor, this is "for the first time, an effective treatment against the most serious form of childhood blindness and a potential paradigm shift towards treatment from the earliest stages of the disease."

Four children, aged one to two, from the United States, Turkey and Tunisia, were selected by specialists from Moorfields and UCL in 2020. The operations were carried out at Great Ormond Street Hospital in London.

These healthy copies of the AIPL1 gene, contained in a harmless virus, were injected into the retina, the light-sensitive layer of tissue at the back of the eye. To avoid any serious risks, however, the treatment was only administered to one eye per patient. The children were then followed for five years before the results were published in the journal Lancet .

Professor James Bainbridge, consultant retinal surgeon at Moorfields and professor of retinal studies at the UCL Institute of Ophthalmology, said children born with ACL can only distinguish between light and dark, and lose what little vision they have within just a few years.

"Some children (who have undergone treatment, editor's note) are even able to read and write after the operation, which is something we would absolutely not expect in this situation, without treatment," he explains.

The parents of one of the children, Jace, described the results as "pretty incredible" and said they were "lucky" to have benefited. Their son, who was two when he started treatment and is now six, can now pick up small objects on the floor and identify toys from a distance.

"I remember crying and getting really emotional," says his father Brendan, "from there it just got pretty unbelievable."

Since the four children received the therapy, seven others have been treated at Evelina Children's Hospital in London by specialists from St Thomas' Hospital, Great Ormond Street and Moorfields.