Gene therapy aims to save sight in 11-year-old girl with rare eye condition
British patient with BBS is second worldwide to receive one-time treatment
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Scientists have developed a one-time gene therapy that may help preserve vision for a child in England with BBS. (Image from iStock)
An 11-year-old girl in England with Bardet-Biedl syndrome (BBS) has become the second person ever to receive an experimental gene therapy designed to preserve eyesight in people with conditions such as BBS that are due to certain genetic mutations.
Catherine L’Estrange, who lives in London, was diagnosed as a baby with the rare inherited condition, which is caused by mutations in the BBS10 gene and marked by an array of symptoms that can include obesity and vision problems. The preteen was given the therapy, being developed by Meiragtx, at the first site in the world to offer it to patients — the St. Helier Hospital in the U.K.
“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,” L’Estrange, who wears glasses, said in a news story published by the St. George’s University Hospitals NHS Foundation Trust. St. Helier Hospital is a major teaching hospital for St. George’s, University of London.
BBS is a genetic disease that affects microscopic, hair-like cellular structures called cilia. One of the most common symptoms is vision problems that eventually lead to blindness.
Called a “world-first gene therapy” by St. George’s, the treatment is administered to patients via a so-called keyhole surgery, where healthy copies of the gene are delivered into the eye.
Mutations in more than 20 different genes can cause BBS. In this child’s case, the disease was caused by mutations in a gene called BBS10. This is the second most common form of BBS.
“Most children with BBS are undiagnosed until at least primary school age, but we had a highly unusual infant diagnosis when Catherine was just a few weeks old,” said Timothy L’Estrange, the girl’s father. “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 color-blind, and continued with her losing her peripheral vision.”
Gene therapy used for second time at London hospital
Meiragtx’s investigational gene therapy is designed to deliver a working version of BBS10 to eye cells via a surgical procedure. Its design is similar to that of Luxturna (voretigene neparvovec-rzyl), a gene therapy approved for a genetic disease, called Leber Congenital Amaurosis, that causes blindness.
“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,” 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. We are excited to see how the results of the gene therapy emerge over [the] coming months.”
The preteen was the second person to receive the therapy at the St. Helier, following a 17-year-old girl from Canada who was treated last year and has chosen to remain anonymous.
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.
“Many teams throughout our hospital group — including ophthalmology, pharmacy, and theatre teams — have worked exceptionally hard to offer hope to children with this rare condition and their families,” said Neruban Kumaran, PhD, a consultant eye surgeon at Epsom and St. Helier University Hospitals NHS Trust. “We’re so pleased to offer this novel treatment through collaboration with Great Ormond Street Hospital and Moorfields Eye Hospital, who helped to identify eligible patients from their specialized clinics.”
According to Kumara, “early positive feedback from the children and their families is very exciting and offers real hope to those affected by this condition.”
Mat Shaw, chief executive of St. George’s, Epsom and St. Helier Hospitals Group, said the entire staff is working to “deliver new, innovative treatments” for patients, such as these two girls, who have BBS10 gene mutations.
“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,” Shaw said. He noted that the experimental gene therapy “aims to stop childhood blindness in its tracks and change what’s possible for the future of children with this devastating condition.”
