At the beginning of 2025, I wrote an article about the different areas of advancement we could expect this year — and the first among them was CRISPR. And it indeed saw breakthroughs!
We are now witnessing one of the most remarkable ones — personalized gene editing. Personalized medicine is great, but personalized gene editing? Incredible.
One wrong DNA letter can lead to a faulty amino acid in a vital protein, and that can cause an ultra-rare genetic disorder. But rewrite or edit that single DNA base, and your baby’s life could change. In other words, editing a single gene could mean the difference between life and death. That’s the power and promise of gene editing.
Coming to the breakthrough itself, a single-gene editing technique (also known as base editing) has helped a baby with an ultra-rare genetic disorder called Urea Cycle Disorder (UCD). In this disorder, the baby had a defective CPS1 gene, which led to a faulty enzyme. Through gene editing, scientists corrected this mutation, and the baby showed remarkable improvement.
Now, you might wonder — what’s the big deal?
It is a big deal. Gene editing is not just scientifically complex; it’s also commercially and logistically challenging. The fact that a detailed base-editing plan was designed and executed successfully in just six months is nothing short of record-breaking.
But here’s the catch — this treatment wasn’t part of a formal clinical trial. It was an emergency compassionate-use case approved by the FDA. So, we don’t yet know how robust or scalable this approach will be.
To address that, several universities and hospitals across the U.S. are now planning clinical trials using this approach. Their main targets will be children with disorders involving a set of seven genes responsible for ammonia detoxification in the body. CPS1 plays a key role in this process — if ammonia isn’t removed from the bloodstream, it can severely damage the brain.
Now, let’s look at the actual technique that helped save the baby’s life. Scientists used lipid nanoparticles (LNPs) containing a guide RNA and an RNA encoding an adenine base editor (ABE). The LNPs were targeted to the liver, as it’s the main site of the urea cycle. By changing just one DNA letter, they restored the production of the full, functional CPS1 enzyme — and the baby’s condition improved dramatically.
The researchers believe that, in principle, the same therapy could be adapted for many patient-specific variants (especially for liver-centered genetic disorders) with only minor changes — such as modifying the first 20 nucleotides of the guide RNA, the PAM sequence, or the deaminase domain. The base-editing components themselves will remain the same as those used for baby KJ.
The FDA will conduct safety checks to assess the quality and consistency of these base-editing components before broader use.
This research stands as a pioneer in precision gene editing — and let’s hope this success becomes the first of many.