- GeneBrief
- Posts
- World's First Personalized Gene Edit Saves Baby
World's First Personalized Gene Edit Saves Baby
From science fiction to survival, CRISPR gets personal.
Mario S
September 30, 2025
GENEBRIEF
Welcome to GeneBrief — your fast, clear guide to gene editing and biotech.
Here’s what we’re decoding in this issue:
🧬 The first ever personalized CRISPR saves a baby’s life
🧠 Scientists made cats glow green to study AIDS.
☕ Lab-grown coffee… without the beans
🔍DEEP DIVE
The Baby Who Got a Custom Gene Edit to Stay Alive
When KJ Muldoon was born, he was already dying.
A rare metabolic disorder, CPS1 deficiency, was flooding his blood with ammonia, a toxin that can shred brain tissue in hours. He was too small for a liver transplant. Meds couldn't touch the root cause: a single genetic typo in his DNA.
So a team at Penn and CHOP did something never done before. They built a gene therapy for one person.
Using base editing, researchers designed a fix tailored to KJ's exact mutation. From sequencing his genome to manufacturing the therapy: six months. FDA approval: one week. That’s not just fast; that’s warp-speed in biotech.
They infused several treatments directly into his body. The results were clear: His ammonia levels plummeted. His body began tolerating protein. He started hitting milestones: sitting up, smiling, holding eye contact. In a matter of weeks, KJ transformed from a terminal case study into a living proof of concept.
“The promise of gene therapy we’ve heard about for decades is finally here,” said Dr. Kiran Musunuru, one of the lead scientists. “And this is just the beginning.”
KJ isn't just a patient. He's a blueprint: standardized delivery, modular editing tools, custom guides for individual mutations. The infrastructure for n-of-1 medicine.
What if your future doctor doesn’t write a prescription...but rewrites your DNA?
⚡QUICK CUTS
Scientists made Cats Glow to Study AIDS
In 2011, researchers inserted a jellyfish gene (GFP) and a rhesus macaque antiviral gene into cat embryos. The glow confirmed the edit took. The real goal: cats that resist FIV, (the feline version of HIV) a potential model for human AIDS research.
Would you Drink Coffee Grown in a Lab?
By 2050, half of coffee-growing land could be gone. Startups are now growing coffee cells in bioreactors. 94% less water, no deforestation. In blind taste tests, most people can't tell the difference.
🧠 BRIEF BYTE
“CRISPR doesn’t just cut DNA – it’s rewriting the way we treat disease.”
-Jennifer Doudna, Nobel laureate
