July 8 (HealthDay News) -- A mutation in a single gene causes catastrophic epilepsy, U.S. scientists say. And that finding, they say, could lead to treatments or a cure for the disorder.

People with catastrophic epilepsy suffer severe muscle spasms, persistent seizures, mental retardation and sometimes autism.

"At present, there is no proven cure to offer children with this specific epilepsy," Dr. Jeffrey Noebels, a professor of neurology, neuroscience and molecular and human genetics at Baylor College of Medicine in Houston, said in a news release from the college. "We now have new clues into the mechanism and have already initiated studies with a new class of drugs not previously explored for this disorder."

Noebels and his team found that a mutation on a gene called Aristaless-related homeobox (ARX) caused catastrophic epilepsy-like symptoms in mice, including muscle spasms, seizures, learning disabilities and reduced social interaction.

When the researchers examined the brains of mice with the mutated gene, they found that interneurons -- a class of cells that inhibit electrical activity in the brain -- had failed to develop in specific areas of the brain.

Mice with the mutation will be "an essential tool to find a cure for the disorder," said Noebels, who is also director of the Blue Bird Circle Developmental Neurogenetics Laboratory at Baylor.

The study is in the July 8 issue of the Journal of Neuroscience.

SOURCE: Baylor College of Medicine, news release, July 7, 2009