Scientists Are Using CRISPR in Attempts to Restore Vision, Cure Blood Disorders, and More

New clinical trials are underway to treat human patients with CRISPR, a technique that edits DNA in cells

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The vast majority of existing medicines only treat symptoms of disease, rather than the root cause of them. But gene-editing technology, which allows scientists to tweak DNA, could lead to outright cures in the not-so-distant future.

At least that’s the promise of CRISPR, a powerful gene-editing tool that could revolutionize medicine. In 2013, scientists published the first study using CRISPR to cut and paste DNA in living human cells in a lab. Now, biotech companies are putting that idea to the test in human patients. A handful of clinical trials using CRISPR are in progress in the United States, Europe, and China.

Likened to molecular scissors, CRISPR’s power lays in its ability to snip out errant bits of genetic code, or replace genes altogether. In the first clinical trials, scientists will attempt the former. Swapping out nonworking genes for new ones is a more complicated undertaking, one that will likely take a few more years of lab and animal testing before it’s tried in people.

Companies have been eager to commercialize CRISPR, with a slew of startups springing up over the past six years, including CRISPR Therapeutics, Editas Medicine, and Intellia Therapeutics. But despite the fervor around CRISPR, these initial human studies demonstrate the abundance of caution with which these companies are approaching gene editing in human beings. They’ll start out treating small numbers of patients. And CRISPR will only be used in the eye, or on cells outside the body at first. That’s to make sure the treatments are safe and won’t wreak havoc on other parts of the genome.

Restoring vision

Genome-editing company Editas Medicine, and pharma partner Allergan, announced in July that they will soon test CRISPR on patients with an inherited form of blindness, called Leber congenital amaurosis 10. People born with this condition have severe vision loss that starts in early childhood, and some of them go completely blind. A mutation in the CEP290 gene causes their…