The finding suggests there may be a way to interfere with or even reverse the mental decline often seen as people with Down syndrome get older. The finding, published in the journal Neuron, also may apply to Alzheimer's disease, the researchers said.

"If we can decrease the expression of this gene [which is called App short for amyloid precursor protein] we may be able to provide something more than supportive care to people with Down syndrome," said a researcher.