This is a “first”: hitherto tested in the laboratory, the CRISPR system known as “genetic scissors” was used on a man suffering from a hereditary form of blindness to correct the genetic mutation at the origin of the disease.
“We have the potential to restore sight to the blind!”. This is not a miracle, but the result of the first use by American scientists of the CRISPR system (called “genetic scissors”) to treat a patient suffering from an inherited form of blindness — Leber’s congenital amaurosis. — caused by a genetic mutation that prevents the production of a protein needed to convert light into signals to the brain.
This disease cannot be treated with standard gene therapy, which consists of providing a replacement gene because it is too large to be integrated into inactivated viruses, the traditional way of transporting new genes into cells.
Delete the disease-causing mutation
“Doctors have therefore chosen to use to treat this patient the famous ‘genetic scissors’ to remove the mutation responsible for the disease by making two cuts on each side of the gene in the hope that the DNA ends will reconnect and allow the gene to operate normally’Explain the Associated Press website which describes this intervention.
The surgical technique used to use the CRISPR system is quite simple: on the patient under general anesthesia, they have, through a tube the width of a hair, pour three drops of a liquid containing this system just under the retina, in the back part of the eye which houses the light-sensitive cells.
The risk of unintended changes to other genes
Scientists have given themselves a month after the intervention to ensure that this process is indeed capable of restoring vision. However, all the tests previously carried out on animals have shown that this treatment made it possible to correct the cells.
If the CRISPR system represents an immense hope in terms of gene therapy, the risk nevertheless exists that its use for the editing of a gene brings involuntary modifications to other genes, thus causing unknown and not necessarily controllable consequences. This is the reason why this medical “first” is observed with attention by the scientific community.
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