On Jun. 16, 2025, the Allen Institute announced that for the first time ever, scientists have developed a precise genetic toolkit that can target the exact nerve cells destroyed by the disease and potentially deliver therapies where they are needed most—a discovery that could dramatically speed up the quest for a cure. The findings were published in the journal Cell Reports. 

Amyotrophic lateral sclerosis (ALS) is a progressive and devastating disease that gradually kills off motor neurons in the brain and spinal cord that control voluntary muscle movement. As these neurons die, people with ALS lose the ability to move, speak, and eventually breathe. Despite decades of research, there’s still no effective treatment or cure. Unlike many other brain cells, motor neurons in the spinal cord have been extremely hard to reach with genetic tools. This has slowed down research and made it hard to test new treatments in the cells that matter most. 

This new genetic tool acts like a “GPS system” to specifically find and label motor neurons—without affecting any other type of cell—offering a new way to study ALS from the inside out and deliver therapeutic agents that could prevent the cells connected to the disease from dying. 

Enhancer AAVs are one type of genetic tool. Scientists began by creating a cellular map by analyzing spinal cord tissue from different species, looking at each cell individually and analyzing their molecular makeup. From that map they found short pieces of DNA, known as enhancers, that work like on/off switches in cells, changing their gene expression and in turn their function or properties in some way.  

These enhancers activate only in specific neurons, making them the perfect tools for delivering targeted treatments or labels to those cells. Researchers then inserted these genetic switches into harmless viruses, along with a glowing protein that lights up under special microscopes to label the cells and verify that the targeting was successfully. These harmless viruses simply act as “delivery trucks” to send a therapeutic or functional cargo into the cell. 

In the short term, researchers can now study how ALS develops in animal models, offering a better understanding of how the disease works. This could lead to new drug targets or biomarkers that tell doctors how fast the disease is progressing. 

Eventually, this same system could be used to deliver gene therapies directly to motor neurons in the brain to protect them and prevent them from dying. Because it targets only the affected neurons, potential treatments could come with fewer side effects.