CRISPR-Cas9 is the cutting-edge genomic technology that essentially lets you target exact sequences in DNA and then cut into them like a knife and insert or remove a gene. You may remember it from that Chinese scientist who successfully (but controversially) implanted gene-edited embryos into a woman who then gave birth to live lab babies. More often, it's used to create things like malaria-resistant mosquitoes or mushrooms that don't brown as fast.
But it does have a lot of practical medical potential, too. It's already been used to remove HIV from a patient's genome. And now, after CRISPRing out a blindness-causing gene from mice, scientists have now successfully scaled-up this procedure to work in a live human body. From NPR:
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In this new experiment, doctors at the Casey Eye Institute in Portland, Ore., injected (into the eye of a patient who is nearly blind from a condition called Leber congenital amaurosis) microscopic droplets carrying a harmless virus that had been engineered to deliver the instructions to manufacture the CRISPR gene-editing machinery.
The goal is that once the virus carrying the CRISPR instructions has been infused into the eye, the gene-editing tool will slice out the genetic defect that caused the blindness. That would, the researchers hope, restore production of a crucial protein and prevent the death of cells in the retina, as well as revive other cells — enabling patients to regain at least some vision.
The procedure, which takes about an hour to perform, involves making tiny incisions that enable access to the back of the eye.