https://www.nytimes.com/2025/05/15/health/gene-editing-personalized-rare-disorders.html

Health|Baby Is Healed With World's First Personalized Gene-Editing
Treatment
  
https://www.nytimes.com/2025/05/15/health/
gene-editing-personalized-rare-disorders.html

  * Share full article
  * 
  * 
  * 1.1k
    1112

You have a preview view of this article while we are checking your
access. When we have confirmed access, the full article content will
load.
A close-up portrait of newborn KJ, who has a tube coming out of his
nose and a tiny felt football next to him. He is swaddled tight and
appears to smile slightly with his eyes closed.
KJ Muldoon was born with a rare genetic disorder, CPS1 deficiency,
that affects just one in 1.3 million babies.Credit...Muldoon Family
Skip to contentSkip to site index
 

Baby Is Healed With World's First Personalized Gene-Editing Treatment

The technique used on a 91/2-month-old boy with a rare condition has
the potential to help people with thousands of other uncommon genetic
diseases.

KJ Muldoon was born with a rare genetic disorder, CPS1 deficiency,
that affects just one in 1.3 million babies.Credit...Muldoon Family

Supported by

SKIP ADVERTISEMENT
Listen to this article * 9:54 min Learn more

  * Share full article
  * 
  * 
  * 1.1k
    1112

Gina Kolata

By Gina Kolata

  * May 15, 2025

Leer en espanol

Something was very wrong with Kyle and Nicole Muldoon's baby.

The doctors speculated. Maybe it was meningitis? Maybe sepsis?

They got an answer when KJ was only a week old. He had a rare genetic
disorder, CPS1 deficiency, that affects just one in 1.3 million
babies. If he survived, he would have severe mental and developmental
delays and would eventually need a liver transplant. But half of all
babies with the disorder die in the first week of life.

Doctors at Children's Hospital of Philadelphia offered the Muldoons
comfort care for their baby, a chance to forgo aggressive treatments
in the face of a grim prognosis.

"We loved him, and we didn't want him to be suffering," Ms. Muldoon
said. But she and her husband decided to give KJ a chance.

Instead, KJ has made medical history. The baby, now 9 1/2 months old,
became the first patient of any age to have a custom gene-editing
treatment, according to his doctors. He received an infusion made
just for him and designed to fix his precise mutation.

Video
transcript
Back
0:00/0:48
-0:00

transcript

Doctors Heal Infant Using First Customized-Gene Editing Treatment

Doctors applied a personalized treatment to cure a baby's genetic
disorder, opening the door to similar therapies for others.

    Developmental moments that he's reaching show us that things are
    working. The prognosis for him was very different before we
    started talking about gene editing and the infusions.

Video player loading
Doctors applied a personalized treatment to cure a baby's genetic
disorder, opening the door to similar therapies for others.Credit
Credit...Children's Hospital of Philadelphia via Associated Press

We are having trouble retrieving the article content.

Please enable JavaScript in your browser settings.

---------------------------------------------------------------------

Thank you for your patience while we verify access. If you are in
Reader mode please exit and log into your Times account, or subscribe
 for all of The Times.

---------------------------------------------------------------------

Thank you for your patience while we verify access.

Already a subscriber? Log in.

Want all of The Times? Subscribe.

Advertisement

SKIP ADVERTISEMENT

Site Index

Site Information Navigation

  * (c) 2025 The New York Times Company

  * NYTCo
  * Contact Us
  * Accessibility
  * Work with us
  * Advertise
  * T Brand Studio
  * Your Ad Choices
  * Privacy Policy
  * Terms of Service
  * Terms of Sale
  * Site Map
  * Canada
  * International
  * Help
  * Subscriptions

  * Manage Privacy Preferences