The dopamine reset: Restoring what’s missing in AADC deficiency

In March 2023, a younger woman got here to Boston Youngsters’s Hospital unable to carry up her head — one hanging symptom of aromatic L-amino acid decarboxylase (AADC) deficiency. This uncommon neurological dysfunction prevents the mind from producing dopamine and serotonin — important chemical substances for controlling motion, temper, and fundamental physique features. With out them, kids expertise muscle weakness, movement disorders, seizures, and developmental delays.

Inside months of receiving a first-of-its-kind gene remedy, the younger woman started to realize head management and shortly after took her first steps. Right this moment, at age 3, she’s thriving.

“Watching her thrive has been nothing in need of miraculous,” says her father. The process didn’t simply give our daughter a brand new life — it gave us one, too.”

“There aren’t phrases to precise how efficient [the therapy] was on this case,” says Phillip Pearl, MD, co-director of Boston Children’s Epilepsy Center, who has overseen the woman’s care.

The household’s expertise serves as a case examine of the influence of a remedy years within the making.

From Parkinson’s analysis to pediatric remedy

The FDA permitted Kebilidi (eladocagene exuparvovec) in November 2024. It’s the primary gene remedy delivered on to the mind to deal with AADC deficiency, and its approval may change the trajectory for sufferers with this devastating dysfunction by addressing the foundation trigger relatively than simply managing its signs.

Kebilidi builds on earlier work in Parkinson’s illness, one other neurodegenerative situation that includes dopamine-producing dysfunction and results in signs like tremors, stiffness, and stability points. AADC deficiency impacts the identical dopamine pathways as Parkinson’s illness — although not by way of neuron degeneration, however as a result of the physique can’t produce dopamine within the first place.

It’s in these similarities that researchers noticed a chance: If gene remedy may restore dopamine in sufferers with Parkinson’s illness, couldn’t it do the identical for many who produce little to no dopamine in any respect?

Growing protected and exact supply

Over the span of greater than a decade, this concept advanced right into a focused remedy strategy targeted on the putamen, part of the mind that depends on dopamine to manage physique motion. Delivering remedy to this space requires a extremely specialised process as a result of the putamen is small and precision is crucial to keep away from damaging surrounding mind tissue. Scellig Stone, MD, PhD, neurosurgical director of Boston Children’s Movement Disorders Program, has been intently concerned in adapting and refining the surgical strategy for supply. After observing early procedures internationally, he and his crew labored on bettering how the gene remedy is infused instantly into the putamen.

“I watched them place the vector into the putamen of a pediatric affected person and I knew this could possibly be improved — and we may do it at Boston Youngsters’s.”

Stone led a multidisciplinary effort to tailor the process for pediatric sufferers — creating surgical protocols, adjusting anesthesia strategies, and coordinating post-operative care to watch neurological operate and security. These efforts had been a part of the SmartFlow Trial, a examine Stone co-authored and that was designed to guage the security and viability of delivering Kebilidi utilizing a specialised MR-compatible cannula beneath real-time MRI steering. The trial concerned three U.S. websites, together with Boston Youngsters’s, and handled a complete of 13 sufferers.

Effecting significant change

Since starting the SmartFlow trial, Boston Youngsters’s has handled a number of kids with AADC deficiency, witnessing enhancements in motor abilities and high quality of life.

“AADC is likely one of the most extreme problems we deal with,” says Pearl, who can also be a co-author on the SmartFlow examine. “However these kids don’t simply enhance, they attain milestones nobody thought potential: head management, sitting up, talking, even strolling. This focused gene remedy, administered instantly into the mind, has been probably the most transformational experiences of my profession, particularly after having adopted kids with this devastating situation over the previous 20 years.”

With greater than 60 sufferers handled worldwide and extra gene and cell-based therapies on the horizon, the success of the AADC trial marks a turning level.

“This remedy proved we will deal with the foundation explanation for a illness within the mind,” says Stone. “It’s a blueprint for what’s subsequent.”

Certainly, Boston Youngsters’s is already conducting new trials, together with these for Rett syndrome, which causes lack of language and motor abilities, and behavioral and neurological issues.

“We’re getting into a second the place our understanding of illness biology, gene supply, and surgical precision are converging,” Stone says. “You’re going to see extra of those therapies popping out over time.”

Be taught extra concerning the Gene Therapy Program at Boston Children’s or contact us to refer a affected person for remedy.