A Breakthrough in Huntington’s Disease

Gene therapy trials in the UK led by professors Sarah Tabrizi and Ed Wild have given
hope to the thousands of people with Huntington’s disease. Until now, this devastating disease
has been incurable. It is an autosomal dominant disease; a child with an affected parent has a
50% chance of inheritance. Beginning in the coding region of the huntingtin gene, an expansion
of the cytosine-adenine-guanine (CAG) trinucleotide sequence occurs. An individual with thirty-
six repeats or more is highly likely to develop the disease, with full expression typically starting
at 40 repeats. With an increased number of CAG repeats, the huntingtin protein makes toxic
versions of said gene, steadily damaging nerve cells. This damage can then lead to involuntary
movement, cognitive decline, psychiatric symptoms, speech difficulties, and even death. While
currently incurable, the results of Tabrizi and Wild’s trials have shown to slow down the
progression of Huntington’s disease in patients by 75% after three years. A drug with the ability
to inactivate the mutant proteins was surgically injected into twenty-nine patients in the UK and
US through a complex 12–20-hour procedure. Scientists utilize a harmless virus to modify it so
that it delivers a specific sequence of DNA into brain cells. The procedure requires surgically
entering two separate regions of the brain through a microcatheter. Once delivered, it instructs
the cells to produce this genetic material that disables the instructions for mutant huntingtin
protein. Throughout the trial, patients undergo testing concerning their motor skills, cognitive
abilities, and the quality of their daily lives. Then, after three years, the results demonstrated a
decrease in progression of an average of 75%, saving more brain cells. With this treatment, those
affected by Huntington’s disease can delay its impact on their health and lead a longer, healthier
lifestyle. Although remarkable, the complexity of the procedure will make the drug unavailable
and expensive for some, and it still must receive approval.

APA Citation

Devlin, H. (2025, September 24). Huntington’s disease treated successfully for first time in UK gene therapy trial. The Guardian. https://www.theguardian.com/science/2025/sep/24/huntingtons-disease-treated- successfully-for-first-time-in-gene-therapy-trial

References

1.Jurcau, A. Molecular pathophysiological mechanisms in Huntington’s disease. Biomedicines 10, 1432 (2022).
2.Kim, A. et al. New Avenues for the treatment of Huntington’s disease. International Journal of Molecular Sciences 22, 8363 (2021).