New CRISPR version could make precision medicine even more precise
CRISPR-Cas9, the so-called "molecular scalpel" that enables the editing or deletion of entire genes, promises exciting new avenues for treatment.
It's arguably true, at least so far, that CRISPR's "hype eclipses early success stories," said Ross Wilson, principal investigator at UC Berkeley's California Institute for Quantitative Bioscience, at the HIMSS Precision Medicine Summit this past June.
But early trials are already showing big promise on some of the most vexing genetic conditions, and we're only about five or 10 years away from seeing genome editing more routinely applied to "things that might be a bit more elective, but could have huge impact, since they're so common," such as Alzheimer's, diabetes and high cholesterol, he said.
In the meantime, a new development just touted in both Nature and Science, researchers from MIT and Harvard's Broad Institute, have discovered a new modification to CRISPR that can fix smaller pieces of an individual's genome – paving the way for even more precise precision medicine techniques.
DNA comprises four nucleobases: A (adenine), C (cytosine), G (guanine) and T (thymine). As explained this week in the MIT Technology Review, they each pair off – A with T, C with G – to create DNA’s double helix shape.
The new approach, called base editing, uses a modified version of the CRISPR tool, allowing researchers to change those letters one at a time, without making breaks to DNA’s structure.
"Standard genome-editing methods, including the use of CRISPR-Cas9, make double-stranded breaks in DNA, which is especially useful when the goal is to insert or delete DNA bases," said David Liu, a Harvard chemistry professor and member of the Broad Institute. "But when the goal is to simply fix a point mutation, base editing offers a more efficient and cleaner solution."
Wilson likened the new technique to swapping out a word in a large paragraph of text, rather than editing out the paragraph itself.
"It’s a lot of DNA to move around," said Wilson of the previous of CRISPR. "With base editing, you could just change the single word."