Gene Therapy for Retinal Blindness?
Gene Treatment of Leber's Congenital Amaurosis Shows Promise in Early Studies
April 28, 2008 -- Gene therapy may improve the sight of people with Leber's congenital
amaurosis, an inherited cause of blindness, two new studies show.
Together, the studies included six patients with genetic mutations that
cause Leber's congenital amaurosis, which affects the retina. Before gene
therapy, the patients had profoundly low vision but weren't totally
Each patient got the experimental gene therapy only in one eye -- whichever
eye had worse vision. Doctors injected the gene therapy into the retina while
the patients were under general anesthesia.
Three of the six patients reported modest improvements in their vision in
low light, beginning two weeks after the procedure. A fourth patient improved
his ability to navigate a simulated street scene and his eye responded better
to light after getting the gene therapy.
The procedure has risks. One of the patients whose vision improved developed
a hole in his macula, the retina's center, which may have been a result of the
surgical procedure that delivered the gene therapy.
The studies appear in the advance online edition of The New England
Journal of Medicine.
An editorial published with the studies notes that while the findings are
"suggestive of efficacy," larger, longer studies with a comparison
group of patients who get placebo treatment are needed to track the procedure's
long-term safety and effectiveness.
The researchers, who included Albert Maguire, MD, of the University of
Pennsylvania's Scheie Eye Institute, and James Bainbridge, PhD, of University
College London's Institute of Ophthalmology, agree with those comments from
editorialist Joan Miller, MD, of the Massachusetts Eye and Ear Infirmary in
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