Winner of Blindness

Under the guidance of scientists from the Perelman Medical School of the University of Pennsylvania, a method of treating patients suffering from Leber congenital amaurosis, and whose diagnosis is due to the presence of a mutation in the CEP290 gene, was developed. The protein encoded by this gene plays an important role in the functioning of photoreceptor cells – sensory neurons located on the retina and responsible for capturing light. Primary photoreceptor blindness associated with this genetic defect is one of the most common forms of Leber's amaurosis. At the moment, this disease is incurable.

Scientists have developed an oligonucleotide – a short RNA molecule – that should reduce the level of mutant CEP290 in photoreceptor cells, thereby restoring the normal functioning of the retina. In the course of clinical trials conducted in the USA and Europe, patients received intraocular injections, through which an oligonucleotide was injected into the eye tissue.

Each subject received at least one intraocular injection into a worse-seeing eye. 3 months after the first administration, half of the patients had improved vision: they were better able to distinguish the direction of light and even letters.

Testing with different intensity of light flashes allowed us to establish that the treated eye, on average, distinguishes six times less bright flashes than before treatment. Thanks to the results of the test with flashes of two different colors, it became clear that the treatment has an effect on cones – a type of photoreceptors responsible for daytime vision.

All the study participants had two different mutations in the CEP290 gene. However, the mutation causing the splicing changes, p.Cys998X, was common to all. The scientists selected the oligonucleotide in such a way that it blocked the mRNA region encoding the defective protein variant before splicing, thereby creating an impressive form of personalized medicine.

Scientists note that research is currently underway that will reveal the presence or absence of delayed side effects, as well as help to choose the optimal dosages for further use.

Article by Cideciyan et al. The effect of an intravitreal antisense oligonucleotide on vision in Leber congenital amaurosis due to a photoreceptor cilium defect is published in Nature Medicine.

Anastasia Poznyak, portal "Eternal Youth" http://vechnayamolodost.ru / based on Penn Medicine News: Injection Improves Vision in a Form of Childhood Blindness.