Physicist Stephen Hawking lived with motor neuron disease for longer than any other person known.Credit: Santi Visalli/Getty
A man with an uncommon type of motor neuron disease experienced improved symptoms and continued to work as a physician a year after becoming the first person to receive a drug designed to target the specific genetic mutation that causes his disease1. Researchers say the early results are exciting and lay the foundation for more treatments for neurodegenerative diseases caused by rare mutations.
The man had a slowly progressing form of motor neuron disease, also called amyotrophic lateral sclerosis (ALS), caused by a rare mutation that leads to protein build-up that contributes to the death of motor neurons. He received an RNA treatment called antisense oligonucleotide therapy. Unlike typical gene therapy, which alters a person’s genes to treat a genetic disease, antisense oligonucleotide therapy, uses short strands of genetic material to target RNA produced by the gene and reduce how much protein is made. The results are published in Med this week.
Steve Vucic, a neurologist and ALS researcher at the University of Sydney in Australia, says the results are an “exciting first step”, although it is too early to know whether the treatment could stop disease progression or be a cure. That will require monitoring the trial participant for another two or three years and testing the drug in more people.
Similar antisense oligonucleotide therapies are the future of treatment for many people with ALS, says Fleur Garton, a neurological disease researcher at the University of Queensland in Brisbane, Australia. Roughly 5–10% of people with ALS have a known genetic mutation. Antisense therapies seem to be safe and can be developed for people with common genetic mutations, for those with rare or even unique mutations, and for people whose disease is caused by multiple mutations, she adds.
Early encouragement
ALS causes motor neurons in the brain and spinal cord to die, leading to symptoms such as muscle weakness, difficulty speaking and progressive paralysis. Most people with the condition eventually require a ventilator to breathe, and death is often caused by respiratory failure. There is no cure and treatment options are limited; The average life expectancy after diagnosis is about two to five years.
The trial participant’s disease is caused by a mutation in the gene CHCHD10, found in fewer than 1% of people who inherit ALS. This gene encodes a protein that enables mitochondria — the organelles that generate the energy needed to power cells — to function properly. Defects in the gene can damage the mitochondria and are thought to contribute to the death of neurons.
The patient received three 50-milligram doses of the drug in his spine, followed by three 75-milligram doses, between April 2024 and April 2025. He did not experience any serious negative side effects, the authors reported. He also showed no signs of cognitive decline, a common symptom of ALS.
A year after the first dose, his blood levels of neurofilament light chain proteins — which are produced by damaged neurons, and so are used as a biomarker for ALS progression — had reduced to the normal reference range. Vucic says this suggests that the treatment could be preserving the neurons in the man’s brain.
Scores on a test that measures motor skills, breathing and neurological function had improved, and other scores for breathing and cognition remained stable. Some people with ALS experience short-term improvements in symptoms without treatment, although study co-author Björn Oskarrson, a neurologist at Mayo Clinic in Jacksonville, Florida, says that sustained improvement without treatment is rare.
Antisense therapies have been developed to target more common gene mutations that cause ALS, but those therapies took at least a decade to make. By contrast, the drug that targets CHCHD10 took only three years to develop, says Oskarrson. Being able to develop a drug to target a specific person’s mutation, test it in animals and then give it to the person within their lifespan was amazing, he adds.
