Beyond CRISPR: The birth of base editing.
As a radiation oncologist, I’m immersed in the world of precision — every radiation beam has to hit its mark. That’s why I find breakthroughs in genetic precision just as thrilling.
There’s a real revolution happening in gene editing right now.
Introduction: A Fanboy Moment for a Scientific Genius
A radiation oncologist’s admiration for precision medicine beyond the beam.
Some worship at the altar of sports, others at religion.
Today, I’m proudly taking a fanboy moment to spotlight a true scientific genius.
Meet the Architect of Precision: David Liu
From Harvard valedictorian to rewriting our genetic code.
I have been reading about Professor David Liu, a molecular biologist at the Broad Institute of MIT and Harvard.
His research combines chemistry and evolutionary principles to deepen our understanding of biology and drive the development of next-generation therapeutics.
Liu is pioneering methods for rewriting our fundamental genetic code with a level of accuracy unprecedented in history.
I’ve been reading about Professor David Liu.
His lab is pioneering some of the most exciting gene-editing tools in existence.
His work is so impactful that it earned him the prestigious Breakthrough Prize in Life Sciences.
What’s remarkable is that one of them is already benefiting patients with severe genetic conditions—translating discovery into clinical impact is always compelling.
Let’s talk about what this former Harvard valedictorian is doing.
The Four Letters That Shape Our Health
How A, G, T, and C can go wrong — and how science is learning to fix them.
Many human diseases arise from errors in the four chemical letters (A, G, T, C) that make up our DNA.
While the Nobel Prize-winning CRISPR-Cas9 technology was a major advance in gene editing, it primarily works by cutting both strands of the DNA helix.
This approach makes it better suited for disrupting faulty genes rather than precisely correcting specific errors, and the cutting process itself can lead to new mistakes.
Beyond CRISPR: The Birth of Base Editing
Fixing mutations without cutting DNA — a safer, smarter approach.
Recognizing that treating most genetic diseases requires fixing these DNA “misspellings,” David Liu’s lab developed a base editing technique.
This approach uses a modified Cas9 protein — altered so it no longer cuts both DNA strands — to guide an enzyme to the target location in the DNA.
This enzyme then chemically converts one DNA letter directly into another (for example, changing a C to a T or a G to an A).
Liu’s team also engineered new enzymes to perform the reverse changes (T to C, A to G).
Why Base Editing Matters
How this breakthrough could fix 30% of all known genetic errors.
Base editing is a new gene-editing technology that fixes genetic mistakes without cutting both DNA strands — something older tools like CRISPR-Cas9 often do.
Instead, it makes precise changes at the exact spot where there’s a problem, which makes it safer and more accurate.
Prime Editing: The “Find and Replace” of DNA Repair
The next-gen tool tackling what base editors can’t reach.
Scientists believe this method could fix about 30% of all known genetic mutations that cause disease.
And it’s not just theory anymore—researchers are already testing the approach in people.
At least 14 clinical trials are underway to determine how well it works.
Beyond CRISPR: The Birth of Base Editing: AATD and the First Human Success Story
One infusion. One gene correction. One powerful proof of concept.
One major milestone: Beam Therapeutics, a company co-founded by scientist Dr. David Liu, used base editing to treat patients with a rare disease called AATD (alpha-1 antitrypsin deficiency).
The team corrected the faulty gene inside the patient’s body with a single treatment.
It is the first time scientists have performed this gene repair on a human being.
Summary
Base editing has been a game-changer, offering a precise way to rewrite faulty genes without breaking the DNA strand.
But even this powerful tool has limits—many mutations, including those caused by missing or extra genetic letters, remain beyond its reach.
To fill that gap, David Liu’s lab developed something even more ambitious: prime editing.
This method can do more than tweak single letters—it can search for and swap entire DNA sequences.
Think of it not as scissors or a pencil but as a word processor with a smart “find and replace” function.
Beyond CRISPR: The Birth of Base Editing: Targeting Cystic Fibrosis — and Beyond
Replacing missing DNA letters with precision and promise.
A small genetic omission disrupts the production of a critical protein that helps regulate salt and water balance in the lungs and other organs, leading to thick mucus buildup, frequent infections, and reduced lung function.
With advanced gene-editing tools, scientists are now exploring ways to precisely correct such mutations at the molecular level, offering hope for lasting treatments or even cures for patients who previously had limited therapeutic options.
Science Without Borders
Liu’s lab shares its discoveries with the world — no paywall, no patents.
Perhaps most inspiring, Liu’s lab didn’t keep these advances behind closed doors.
They shared their tools with the world, placing genetic instructions in an open-access library now used by thousands of research groups globally.
This story powerfully reminds us that the future of medicine isn’t just about innovation — it’s about collaboration.
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