In the lab, a genetic 'correction' drug lets motor neurons talk again — aimed at a defect shared by 97% of patients

The backstory: why most patients still have no treatment aimed at the cause

Motor neuron disease, known in many countries as amyotrophic lateral sclerosis, or ALS, gradually destroys the nerve cells in the brain and spinal cord that control muscles. As it advances, people lose the ability to move, speak, swallow, and breathe. King's College London says it is estimated to affect 1 in 300 people in their lifetime, and there is no cure.

Approved and experimental treatments already exist for two rare genetic forms of ALS, which account for under 3% of cases. For the remaining 97%, there has been no significant disease-modifying treatment. Those cases share one feature: a protein called TDP-43 stops doing its job. In healthy cells it acts like a proofreader of genetic material. When that proofreading fails, neurons can make faulty proteins that cannot do their usual work.

What the lab study found

On November 11, King's described a new study published in Nature, with authors from King's, University College London, the Francis Crick Institute, Leibniz-FMP, and Trace Neuroscience. By recreating in the lab what happens in human neurons when TDP-43 fails, the researchers found a knock-on effect: errors in the production of another key protein, UNC13A, which normally lets neurons send signals to each other. Common genetic variants in UNC13A are already among the strongest known risk factors for the disease.

The study found that a single error in how UNC13A is produced drastically reduced communication between neurons. The team designed a type of drug called an antisense oligonucleotide, or ASO, to target that error. An ASO is a short, synthetic piece of genetic code that can steer a cell to skip or correct a faulty stretch of instructions. In human neurons in the lab, it restored production of functional UNC13A protein and let the cells communicate again.

"We were surprised to see that restoring just one genetic event, out of the hundreds disrupted, was enough to allow neurons to talk to each other again," said Juan Burrone, professor of developmental neurophysiology at King's. Pietro Fratta, professor of cellular and molecular neuroscience at UCL and a group leader at the Crick, said the work shows UNC13A is the main driver of synaptic release deficits when TDP-43 fails, and that the team has developed antisense oligonucleotides that effectively rescue this deficit.

How this relates to trials already underway

This needs to be stated plainly: the paper shows results in laboratory models using human neurons, not a cure already demonstrated in patients.

King's also noted that another ASO targeting UNC13A dysfunction through a similar mechanism is already in clinical development in humans in the UK, Europe, and China. Last month, the first UK participants were dosed with TRCN-1023 in Trace Neuroscience's Phase 1/2 FUNCTION ALS trial, and UCL is a participating site. Rachel Jackson, one of the paper's first authors, who did the work as a research associate at King's, said it was especially exciting that a similar therapy is now being tested in clinical trials and could potentially help people living with the disease. That trial is still at an early stage, and it does not yet show that the approach works in patients.

What it could mean for you

If later human trials confirm this path, the target would not be one extremely rare mutation, but a defect shared by most patients. That would be a large difference. What is confirmed today is narrower: fixing one genetic error in the lab was enough for neurons to communicate again, and a closely related drug has entered early human testing. There is still a required stretch of trial work between a dish of cells and a treatment that changes patients' lives.

Original source published: King's College London, Nov 12, 2026, 00:00 Beijing time (UTC+8)