The Hunt to Cure Charcot-Marie-Tooth Type 4B3

Iris Schultz first learned that her three-year-old son Hunter Schultz had Charcot-Marie-Tooth disease type 4B3 over a Zoom call in May 2020. Hunter had been missing milestones from infancy, but doctors kept reassuring Schultz that he was healthy and would catch up. Now, she learned that was not the case. CMT4B3 is a progressive, inherited neurological disorder that attacks the peripheral nerves; causes deterioration in patients’ ability to walk, grasp, see, and hear; and eventually leads to premature death. 

“We were completely blindsided,” Schultz says. “After being told by more than 20 doctors that he was completely fine, all of a sudden, we had a very sick child.”  

Doctors told Schultz that there were no treatments or clinical trials for CMT4B3 and that the only option was to watch the disease progress. But she refused to accept that nothing could be done. She began reading scientific papers about the gene responsible for CMT4B3, reaching out to researchers across the world, and connecting with two mothers who had driven the development of treatments for their own children’s rare diseases. 

“I remember thinking, if they could do it, I can do it,” she says. “I just want to be able to tell Hunter when he’s older that I did everything I possibly could to help him.” 

With that determination, Schultz and her husband Brett founded Hunters CMT4B3 Research Foundation, a nonprofit dedicated to accelerating translational research for CMT4B3 and related neuromuscular disorders.  

“What began as our family’s desperate search for answers has grown into a powerful engine for driving scientific discovery,” Schultz says. 

According to Schultz, one of the most promising projects the foundation is funding is at the Chua Lab at the Johns Hopkins Institute for Cell Engineering. The work of Jason Chua, MD, PhD, focuses on the process of autophagy, or the way a cell gets rid of aging components or toxic materials to help preserve its health. In many neurological disorders, like CMT4B3, this process is disrupted.  

Using stem cells, including those derived from Hunter himself, Chua and his team have created a cellular model of the disease that mimics the biology of CMT4B3 in the lab. This living model allows scientists to study exactly how autophagy is disrupted and to test potential therapies, including repurposed drugs already approved by the FDA for other conditions—an approach that could dramatically shorten the path to treatment. 

“My lab’s personal goal is to use our platform to get precision medicine interventions to a point where they’re able to go into clinical trial within the next two years or less,” says Chua. 

Beyond CMT4B3, Chua’s team is also leveraging these models to explore therapies for other disorders linked to autophagy defects, such as Parkinson’s disease and beta-propeller protein-associated neurodegeneration (BPAN). 

He says none of this work would have been possible without philanthropic support. 

“The funding climate for many research labs is uncertain and challenging due to changes impacting traditional funding mechanisms,” Chua explains. “Support from foundations like Hunters CMT4B3 Research Foundation is absolutely critical. It allows us to pursue high-risk, high-reward science that can truly change lives.” 

In addition to the Chua Lab, the foundation is partnering with Jefferson Doyle, MD, SPH ’04 (MHS), Med ’15 (PhD), at the Wilmer Eye Institute, to investigate how CMT4B3 affects vision—a lesser-known but often severe complication of the disease. Their collaboration aims to understand the mechanisms of eye involvement and to develop new therapeutic strategies for pediatric genetic eye disorders. 

Today, Hunter is a vibrant eight-year-old who loves Minecraft, LEGO, and playing with his friends. But behind his bright smile, the disease continues to progress, making it increasingly difficult for him to walk, see, and speak. He works for hours each week through physical, occupational, speech, and vision therapy to maintain his skills. 

“He works harder than anyone else I know,” Schultz says. “He’s resilient, and we’re just so proud of him.” 

The foundation and researchers continue their work, too. Schultz says the hope of a breakthrough, one born from her family’s determination and the tireless work of scientists like Chua and Doyle, keeps them going. 

“Science gives me hope,” Schultz says. “The advancements in the field since we started the foundation five years ago are mind-boggling. There have been countless rare diseases that now have treatments. We just need to push harder. We know it’s not if, but when.”