Ricki Lewis

Last year, nine-month-old KJ Muldoon made history when a variation of CRISPR gene editing, called base editing, swapped one DNA building block for another at a specific part of his mutant gene. He had inherited a urea cycle disorder called carbamoyl-phosphate synthetase 1 (CPS1) deficiency. It hampers the ability to digest protein and is among the rarest of the rare, affecting only about one in 800,000 to one in 1.2 million newborns, in different populations.

The boy had inherited one mutation from each parent; they are unaffected carriers. His liver couldn't produce the crucial enzyme CPS1, and as a result, ammonia released from the breakdown of the amino acids in dietary proteins was accumulating in his bloodstream. Organ failure and, ultimately, brain swelling and coma would follow. Half of the babies with the condition do not survive infancy.

KJ's case was reported in The New England Journal of Medicine May 15 of last year, "Patient-Specific In Vivo Gene Editing to Treat a Rare Genetic Disease." DNA Science covered it here.

More recently, KJ appeared at a news conference March 2, 2026, to celebrate Rare Disease Day. The toddler demonstrated his ability to walk. He has very mild symptoms of the ultrarare disease.

To continue reading, go to DNA Science, where this post first appeared.

Organoids are tiny bits of organs nurtured in lab glassware from stem cells. I joke about them at Halloween, when a few drops of water on tiny sponge brain and heart precursors bloom into mini-organs.

A Bridge Between Animal Models and Clinical Testing

Real organoids are a brilliant tool to investigate biological processes and test new treatments. Induced pluripotent stem (iPS) cells are grown from a patient's skin fibroblast cells, providing a platform to test individualized interventions. And iPS cells are much closer to the human condition than a fruit fly, worm, zebrafish, rodent, or even a primate model.

Organoids aren't complete replicas of organs, but mimic how cells assemble into tissues of a specific organ, and how those tissues interact. They offer an increasingly important step between testing a treatment in an animal model and in people in clinical trials, saving time and funding and improving safety and efficacy.

The most recent report of a novel organoid to capture my attention is a mini human spinal cord, which researchers at Northwestern University created to model different types of injuries to test regenerative treatments. Like a spinal cord in a body, these miniature bits of humanity display inflammation, cell death, and the clumping of glial cells into impenetrable scar-like masses that can squelch nerve healing and regeneration.

To continue reading, go to DNA Science, where this post first appeared.

I have a curious relationship with AI.

A few years ago, I began to notice that when I posed a query on a topic in genetics – for a DNA Science post or to update my textbook Human Genetics: Concepts and Applications with McGraw-Hill – an answer would pop back that read curiously like my own words. Likely, they were.

So I wasn't terribly surprised when, a few months ago, a notice appeared in The New York Times and elsewhere: "Anthropic to pay authors $1.5 billion" in a class action lawsuit brought by three authors. Fourteen of the half million "works" that the company copied, to train its chatbot Claude, were mine!

AI Saves Time, Provides Details

Right now, I'm working on the next incarnation of my textbook. Editions are outdated, I'm told, so this is a revision – not much of a difference. To update in this age of AI, I still scrutinize new research findings, led to journal articles through old school press releases in my email.

But AI is becoming increasingly helpful in handling the minutiae, of quickly updating a statistic or other detail. What does screening the genome of an early embryo cell cost? How are cancer immunotherapies selected for a particular patient? Which single-gene diseases are amenable to correction using CRISPR?

To continue reading, go to DNA Science, where this post first appeared.