NIH scientists lay foundation for potential gene-editing therapy for late-onset Tay-Sachs

Friday, August 15, 2025

Study of human cells and mice may have implications for other lysosomal storage disorders

Scientists at the National Institutes of Health (NIH) successfully reduced the severity of late-onset Tay-Sachs (LOTS) disease in human cell cultures and a mouse model by using a novel gene-editing treatment. LOTS is a rare form of Tay-Sachs disease, with signs and symptoms such as muscle weakness, loss of coordination, muscle spasms, and sometimes loss of mental function beginning in late childhood to adulthood. Similar disorders for which this breakthrough has implications include GM1 gangliosidosis, Sandhoff disease, Niemann-Pick disease, Krabbe disease and Gaucher disease.

LOTS is a genetic disorder caused by a mutation in the HEXA gene that causes a deficiency of an enzyme that is critical to breaking down a fatty substance in the brain, known as GM2 ganglioside. The buildup of this fatty substance damages nerve cells in the brain and spinal cord. The amount of enzyme still being produced by the body affects the severity of the disease and the age of onset. By deploying the correction to the HEXA gene, scientists were able to increase the activity of the enzyme, known as beta-hexosaminidase A, delay symptom onset and significantly extend lifespan in the mouse model.

“With LOTS, a slight correction will go a long way. This editing may only need to increase enzyme activity by about 10 percent to keep symptoms from getting worse, and improve their quality of life,” said paper author Dr. Richard Proia of NIH’s National Institute of Diabetes and Digestive and Kidney Diseases. “We’ve figured out that opening the door to increased enzyme activity is possible, now we have to figure out how to do it in a person.”