'My girl's going blind but may have had her sight saved by pioneering op'

'My girl's going blind but may have had her sight saved by pioneering op' Catherine L'Estrange, aged 11, has Bardet-Biedl syndrome (BBS) which would eventually rob her sight but a new treatment injected into her eyeball could change that An 11-year-old girl has become the first Brit to have pioneering gene therapy for a rare condition that leaves people blind by their early 20s. Catherine L'Estrange was diagnosed with Bardet-Biedl syndrome (BBS) as a baby and has undergone the procedure which had only been performed on one other person in the world. The condition is caused by a gene mutation and to save Catherine’s sight surgeons injected healthy copies of the gene directly into her eye. Catherine, from North Acton, west London, said: "If this treatment works, it will help me to carry on seeing things around me, and most of all I will be able to carry on reading books, which is one of my favourite things to do." People with BBS slowly go bling as they grow up as small cells in the retina die. To halt this, surgeons removed the jelly inside Catherine’s eye and injected healthy copies of the BBS10 gene into the retina, which is the light sensitive layer of tissue at the back of the eye. Her father, Reverend Timothy L'Estrange, said: "Our whole family has been so grateful for the opportunity to save Catherine's vision - it will be absolutely life-changing for her to retain any vision at all." BBS affects around one in 100,000 births in the UK. As well as vision loss, BBS can also cause kidney problems, learning difficulties and obesity. Patients sometimes have extra fingers or toes. The gene therapy, developed by biotechnology company MeiraGTx, was given to Catherine as part of an hour-long procedure at St Helier Hospital in March. Neruban Kumaran, consultant eye surgeon at Epsom and St Helier University Hospitals NHS Trust, said: "By giving a healthy copy of the gene, it helps save those cells, and the hope is to either stabilise or improve vision. “One of the things that causes a lot of anxiety [for parents] is the worry that these children lose vision and possibly lose their independence. "There's no other treatment for this, and so the opportunity to protect vision or improve vision, or give them hope that they won't lose their vision and they can maintain that independence, it really means a lot." The BBS10 gene is one of 20 that can be faulty in BBS patients. The team of medics at St Helier worked with experts at Great Ormond Street and Moorfields Eye Hospital to identify eligible patients as young children with this specific mutation. Reverend L'Estrange said most children with BBS do not get diagnosed until they are in primary school, but Catherine was diagnosed at just a few weeks old. He said: "Our policy was to develop her independence and resilience as much as possible, ready for the inevitable loss of her sight, which began with her becoming night-blind, then colour-blind, and continued with her losing her peripheral vision. "We were told that possible gene therapy was many, many years away, and was likely to arrive after Catherine had entirely lost her sight - so we were surprised and delighted when we learned this treatment had become available, and that Catherine would be one of the first patients in the world to receive it." Just one of Catherine's eyes has been treated with the new gene therapy, with the team now waiting to see the results. Only one other person - a 17-year-old girl from Canada - had received the treatment before Catherine. Her procedure took place at St Helier in August last year. The parents of the girl, who wishes to remain anonymous, said: "This treatment has given our daughter a precious chance to preserve her vision, and we hope it will become a life-changing therapy for children with BBS10 all over the world." Since Catherine, the procedure has also been performed on one other younger child with BBS. After having the therapy, patients are seen in clinic and have various sight tests, such as reading from a chart and identifying different shades of colours. Mr Kumaran said some have already said their vision is better in dim light and the feedback so far has been positive, though it will take years before the full results are known. He said: "There is a hope that it may improve vision slightly, but it's difficult to say. It's not going to leave someone with perfect vision. But the hope is to stabilise and/or improve vision. Only time will tell. "There's been some very positive feedback from a mixture of the patients and the families that suggest their vision may be better. Early reports from the families have been very promising, and it gives us lots of hope. But in practice, it will take many years before we're sure." Mat Shaw, chief executive of St George's, Epsom and St Helier Hospitals Group, said: "As a father, I can't imagine how it feels to watch your child slowly go blind, and I'm so proud that our teams are offering hope to these children and their families, which aims to stop childhood blindness in its tracks and change what's possible for the future of children with this devastating condition."