A 5-year-old boy from Essex, England, named Edward, son of Megan Willis has achieved significant motor milestones, including walking independently, after being treated with the gene therapy Zolgensma through the National Health Service (NHS).
Edward was diagnosed with spinal muscular atrophy (SMA) as an infant and received the one-time gene therapy in 2021 under a landmark NHS agreement making the treatment available in the United Kingdom as reported by BBC News.
Spinal muscular atrophy (SMA) is a rare, genetic neuromuscular disorder caused by mutations in the SMN1 gene, which leads to insufficient production of the survival motor neuron (SMN) protein critical for the health and survival of motor neurons. When SMN protein levels are low, motor neurons deteriorate, resulting in progressive muscle weakness, loss of motor abilities including sitting, standing and walking, and in severe cases difficulty breathing and swallowing. 2
SMA is usually classified by severity and age of symptom onset. In its most severe forms, children may never achieve major motor milestones and may not survive beyond early childhood without treatment. Genetic testing and newborn screening can identify SMA early, which is important for prompt intervention. 2
Zolgensma (generic name: onasemnogene abeparvovec-xioi) is a gene replacement therapy designed to target the underlying genetic cause of SMA by delivering a functional copy of the SMN1 gene to a child’s motor neuron cells. This gene is carried into the body using a modified adeno-associated virus (AAV) vector and administered as a one-time intravenous (IV) infusion. Once delivered, the new gene enables cells to produce SMN protein, which helps to halt progression of the disease.
Zolgensma was approved by the U.S. Food and Drug Administration (FDA) in 2019 for use in children under 2 years old with genetically confirmed SMA and has since been approved or authorised in numerous other countries, including conditional authorisation across Europe, including the UK.
While Zolgensma does not reverse pre-existing nerve damage, early treatment can slow or stop disease progression, improve motor function and increase survival without permanent ventilation or need for intensive supportive care when given before significant symptoms develop.
Edward was diagnosed with SMA when he was about two months old. In March 2021, the NHS England struck a confidential agreement with the manufacturer to provide Zolgensma at a price deemed fair for the public health system, making it one of the first cases in the UK to receive the therapy under national health coverage.
Since receiving the one-time infusion of Zolgensma, Edward has experienced remarkable progress in motor skills that were once unlikely at diagnosis. His mother, Megan Willis, told the BBC that Edward can now walk independently, swim, ride a jet ski, and engage in everyday activities typical for his age group.
Although Edward may still use a wheelchair at some stage in life, his current abilities reflect significant improvement compared with expectations for untreated SMA. His ongoing care includes physiotherapy multiple times per week to maximise mobility and motor function.
According to the NHS and clinical experts, Edward is one of more than 150 children treated with Zolgensma in England through similar arrangements. A medical director at NHS England has described the therapy’s effects as substantial for multiple patients, reflecting the potential of gene therapy to transform outcomes for children with SMA when administered early.
Families of children with SMA often require ongoing multidisciplinary care, including physiotherapy, orthopaedic interventions like hip surgery, and continued monitoring of motor abilities and general health.
But the main limitation with Zolgensma is its affordability, it costs more than 2 million US dollars.
Gene therapy like Zolgensma represents a cutting-edge medical approach for rare genetic disorders by targeting their root causes rather than only managing symptoms. For inherited conditions like SMA, this therapeutic strategy offers the potential to alter the disease trajectory, especially when applied before irreversible nerve damage occurs. 2
The development and approval of Zolgensma has also spurred further research into similar gene therapies and expanded treatment options for other age groups and related conditions. Some newer gene therapies emerging from this field aim to extend benefits to older patients or different genetic disorders.
In SMA, the lack of SMN protein causes motor neurons the nerve cells that control muscle movement to degrade, leading to muscle weakness and loss of function. Zolgensma supplies a working copy of the SMN1 gene into these neurons. As the corrected gene is expressed, cells can produce sufficient SMN protein, which helps preserve motor neuron function and supports improved muscle movement and survival. Because the therapy is given once intravenously, it avoids repeated dosing, unlike other treatments for SMA. 2
References
Johns Hopkins Medicine. “Spinal Muscular Atrophy (SMA).” Accessed 1st January 2026. https://www.hopkinsmedicine.org/health/conditions-and-diseases/spinal-muscular-atrophy-sma.
Zolgensma. “Zolgensma (onasemnogene abeparvovec-xioi).” Accessed 1st January 2026. https://www.zolgensma.com/.
Frontiers in Pharmacology. “Gene Therapy in Spinal Muscular Atrophy: Mechanisms, Progress and Perspectives,” Frontiers in Pharmacology 15 (2024). https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1475884/full.
Pearson, Steven D., Praveen Thokala, Mark Stevenson, and David Rind. “The Effectiveness and Value of Treatments for Spinal Muscular Atrophy.” Journal of Managed Care & Specialty Pharmacy 25, no. 12 (December 2019): 1300–1306. https://doi.org/10.18553/jmcp.2019.25.12.1300.
