Gene therapy against rare hereditary blindness
Researchers have been able to replace defective genes in chick embryos that cause an animal variant of what is known as Leber's congenital amaurosis (LCA) in humans. They were even able to prevent the outbreak of the disease.
The rare hereditary LCA causes retinal malformations, severe visual impairment and blindness in children at an early age. The scientists led by Susan Semple-Rowland from the University of Florida believe that there is now evidence that gene therapy against the disease is at least theoretically promising.
Semple-Rowland's team introduced virus-injected replacement genes for the pathologically mutated GUCY2D gene into the eyes of chicken embryos. Mutations in this gene are also responsible for LCA type 1 in humans, which accounts for around 20 percent of all cases of the disease in children. The defective gene causes the photoreceptors in the eye to become unresponsive to light and degenerate, eventually leading to the breakdown of the retina. However, this development did not occur in six out of seven gene-treated chicks, although only a few retinal cells had also been infected by the virus gene shuttle.
Before the first clinical tests on humans, it still has to be confirmed that the virus is also harmless to humans.
