New treatment improves sight for children with rare genetic condition
21 February 2025
Four children have gained life-changing improvements in sight following treatment with a pioneering new genetic medicine through Moorfields Eye Hospital and UCL Institute of Ophthalmology.
The work was supported by the National Institute for Health and Care Research (NIHR) and Moorfields Eye Charity.
Due to a rare genetic deficiency known as Leber congenital amaurosis (LCA), the children who received this treatment were born with only sufficient sight to distinguish between light and dark. Most children with the condition lose their sight as the gene defect causes retinal cells to malfunction.
This new treatment involves injecting healthy copies of the faulty gene into the retina. The copies are packaged inside a harmless virus, which enables them to penetrate the retinal cells.
For safety reasons, the children could only receive the gene therapy in one eye. The children lost sight in their untreated eye, but all saw remarkable improvements in their treated eye.
The outcomes of the new treatment, reported in The Lancet, show that gene therapy at an early age can dramatically improve sight for children with this severe condition.
Professor Michel Michaelides, consultant ophthalmologist at Moorfields Eye Hospital and Professor of Ophthalmology at the UCL Institute of Ophthalmology, commented:
We have, for the first time, an effective treatment for the most severe form of childhood blindness, and a potential paradigm shift to treatment at the earliest stages of the disease. The outcomes for these children are hugely impressive and show the power of gene therapy to change lives.
Professor James Bainbridge, consultant retinal surgeon at Moorfields Eye Hospital and chair of retinal studies at UCL Institute of Ophthalmology, added:
Sight impairment in young children has a devastating effect on their development. Treatment in infancy with this new genetic medicine can transform the lives of those most severely affected.
Moorfields Eye Charity has supported Professor Bainbridge’s work as the Chair of Retinal Studies, enabling the expansion of this programme of experimental medicine, including the initiation of gene therapy trials.
Jace from Connecticut is one of the children who received treatment. His parents, Dani and Brendan, shared their experiences:
We spent months talking to doctors, hearing their hypotheses, until a retinal referral confirmed he [Jace] has an aggressive form of LCA (Leber Congenital Amaurosis). By chance, at a charity’s conference, we met Professor Michaelides, who told us of his research work at Moorfields, and we were accepted for this experimental treatment.
Jace coming out of surgery
We are so grateful for this opportunity, and for the care he’s received; we feel we have friends now at Moorfields. When first offered the chance to participate, we wanted to give him everything we could to successfully navigate the world. We also understood the huge implications for future research, and how participating could help others. It has been a phenomenally positive experience, and the results are nothing short of spectacular.
Jace with his dad, Brendan
After the operation, Jace was immediately spinning, dancing and making the nurses laugh. He started to respond to the TV and phone within a few weeks of surgery, and within six months, could recognise and name his favourite cars from several metres away; it took his brain time though, to process what he could now see. Sleep can be difficult for children with sight loss, but he falls asleep much more easily now, making bedtimes an enjoyable experience.
Jace with his mum, Dani
The four children who were given treatment are from America, Tunisia and Turkey. They were seen at Moorfields Eye Hospital’s Clinical Research Facility, and the procedure took place at Great Ormond Street Hospital.
Gene therapy is already being used by the NHS for RPE65 deficiency which causes Leber’s congenital amaurosis and other forms of retinal degeneration which are associated with early-onset blindness. These new findings offer continued hope that genetic medicine will benefit more affected children.
The team are currently exploring ways to make this new treatment more widely available.
