A gene variant associated with long lives in those people who possess it may also make them smarter by improving brain function, researchers say.

The gene is responsible for the creation of a hormone that's been dubbed Klotho, after one of the three Fates of Greek mythology, the one who spins out the thread of human life.

The presence of the hormone in seniors may help counteract the normal cognitive decline associated with advancing age, the researchers said.

"What we've discovered is a cognitive enhancer," said study lead author Dena Dubal, a neurology professor at the University of California, San Francisco.

"This may represent a new way to treat problems of cognition in the brain" ranging from schizophrenia to Alzheimer's disease, she said.

It has been known for at least decade people with high body levels of Klotho tend to live longer, and researchers wanted to know if the hormone could protect our brains from aging as well as the rest of the body.

In aging studies with around 700 participants, the researchers found people possessing life-extending variations of the Klotho gene -- about one in five of the participants -- had higher scores on cognitive tests.

And the effect wasn't limited to older people, the researchers discovered in subsequent research.

"Those that carried the genetic variant that increased their Klotho levels showed better cognitive performance across the lifespan," Dubal said..

At any stage of life, people with high Klotho levels scored better on tests gauging memory, learning, attention and language, she said.

In tests on mice designed to find out the mechanism by which Klotho improved cognition, the researchers discovered it was strengthening connections between cells in the brain in areas that are involved in memory and learning.

Those findings suggest a drug that could increase Klotho levels might be an aid for people who suffer from Alzheimer's and related brain diseases, the researchers said, although they acknowledge the possibility of such treatments is likely years away.

Still, the new study is a step forward, says Molly Wagster of the National Institute on Aging, where she oversees research into cognitive changes.

"The beauty of this study is that the finding gives us another place to look, another path to take as we try to determine targets for the development of drugs," she says.