Proof that gene therapy can treat genetic disorder of the retina

Gene therapy has been used successfully to improve visual function in a patient with a genetic disorder of the retina, Leber's congenital amaurosis (LCA), as reported in a study published online ahead of print by the New England Journal of Medicine.

Professor Robin Ali of the Institute for Ophthalmology led the trial. James Bainbridge, consultant surgeon at Moorfields Eye Hospital, UK, administered subretinal injections of recombinant adeno-associated virus vector 2/2 expressing the gene that is mutated in this form of LCA to three young adult patients. No serious adverse events were reported.

Each of the three patients had a modest, subjective improvement in visual acuity; none showed a change in retinal responses on electroretinography, and Goldmann perimetry showed no clinically significant change in visual acuity or in peripheral visual fields, but it is hoped that their vision will no longer continue to deteriorate. One patient demonstrated significant improvement in visual mobility (subjective), visual function in microperimetry and on dark-adapted perimetry.

Thus the researchers concluded that gene therapy may be used successfully to treat a specific genetic disorder of the retina. Following this proof of concept, Professor Ali plans to increase the dose and to treat younger, potentially more adaptable, patients.