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:

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.

Researchers partially restored hearing in deaf mice with a certain kind of genetic hearing loss by inserting working copies of the mutated genes. Eventually the technique could lead to gene therapy for certain causes of human deafness. Read the rest