North Texas girl to become first patient to receive treatment for rare genetic disorder microbiologystudy

An 11-year-old from Rowlett is set to make medical history as the first person in the world to receive treatment for NARS1.

Marley Mansour was diagnosed in early 2023 after years of unanswered questions. The rare genetic disorder affects protein production in the body, leading to developmental and neurological challenges.

She is one of fewer than 100 people globally who have been identified with the condition, according to her doctor, Kaitlin Batley, an assistant professor of pediatrics and neurology at UT Southwestern Medical Center.

The treatment is antisense oligonucleotide therapy, commonly called ASO. This type of genetic therapy uses short, synthetic DNA sequences to target specific mRNA. N-Lorem, a California-based nonprofit organization, is developing the treatment and helping create personalized medicine for Marley.

The approach targets Marley’s specific genetic mutation, aiming to correct the underlying issue at the molecular level.

“To access treatment, a research physician in a research medical center needs to complete an application on our website and explain all the details about the mutation,” said Dr. Stanley Crooke, CEO of n-Lorem. “We must know everything about it to determine whether we can help.”

The ASO will be administered through a spinal tap, her doctor said, and is designed to help Marley’s body produce the necessary proteins to curb her communication difficulties and peripheral neuropathy.

“Communication is a big struggle for her; she can’t converse with us,” said Kayla Mansour, Marley’s mom. “She can’t tell us where it hurts in her body… and that’s one of the things we’re terrified of. What if she can’t tell us something hurts or something’s wrong?”

Science behind the treatment

Though still investigational, the Food and Drug Administration has approved the ASO therapy targeting the NARS1 mutation, offering hope for Marley’s condition.

NARS1, short for asparagine-tRNA synthetase, is critical in protein synthesis. Mutations of this gene disrupt the body’s ability to produce proteins, leading to various symptoms, including developmental delays, seizures and motor skill challenges.

According to Crooke, Marley’s specific mutation is a toxic variant, which means her body produces a harmful form of the protein.

“She has a mutation that makes a protein worse for her,” Crooke said. “She has one good gene, one bad gene. That means she makes one good molecule of RNA and one bad molecule of RNA, one good molecule of protein, one bad molecule.”

The ASO therapy will target and neutralize the defective RNA, allowing her healthy RNA to function correctly.

A new frontier in medicine

N-Lorem, founded by Crooke, specializes in developing free, individualized ASO treatments for patients with ultra-rare conditions.

In 2022, n-Lorem had helped 150 nano-rare patients, evaluated over 300 applications, accepted over 140 patients into its program and had already treated 15 patients, according to their website.

“We only work with what we know and are doing, and we are confident we can do what we need to do safely,” Crooke said. “A watchword for us is to not harm.”

The treatment journey has not been without challenges. The Mansour family faces significant financial burdens, as insurance does not cover clinical trial-related hospital expenses. Costs are expected to reach six figures over the two-year trial period.

Crooke told The Dallas Morning News that each treatment costs about $1.2 million and is funded through donations, grants and partnerships. The nonprofit will cover the cost of the treatment for life, but Marley’s family is responsible for any clinical-trial-related hospital expenses not covered by insurance.

While Marley’s treatment is specific to her mutation, it sets a precedent for other NARS1 patients with similar genetic profiles. This breakthrough could pave the way for more accessible therapies for those with ultra-rare diseases, according to Crooke.

2025 The Dallas Morning News. Distributed by Tribune Content Agency, LLC.