WEDNESDAY, June 25 (HealthDay News) -- Researchers say they've discovered a gene that may make it easier for people to develop Alzheimer's disease, and it could become a target for drug treatments.

"This new work not only provides a better understanding of the mechanism leading to the disease, but identifies a risk factor as an important target for therapy," said Philippe Marambaud, an assistant professor of pathology at the Albert Einstein College of Medicine in New York City and member of an international team of scientists that released its findings Wednesday.

Alzheimer's disease, which causes senility and can lead to death, affects an estimated 5.2 million Americans. The Alzheimer's Association predicted earlier this year that it will strike one in eight Baby Boomers, and that number is expected to climb as the population ages.

The disease is incurable, and treatments have a limited impact. However, scientists think they understand how the disease develops as bits of protein called amyloid plaques clog the brain.

In the new study, published in the June 27 issue of the journal Cell, scientists from several countries studied the human genome and discovered a gene whose variations may make Alzheimer's disease more likely.

Variations of the gene, known as CALHM1, open gates on the surfaces of brain cells and allow calcium to get inside them, potentially leading to Alzheimer's disease, Marambaud said.

"If you carry this risk factor, you are at risk for developing Alzheimer's disease," although it's not guaranteed that you will get it, he said. People with a copy of a single type of the gene variation appear to be 1.44 times more likely to develop Alzheimer's disease, with an even higher risk for those with two copies of the abnormal gene.

The findings "open up big avenues for research," Marambaud said, allowing scientists to test whether drugs will disrupt the effects of the genetic trait.

"This is a long process. We are really at the initial steps of design," he said. "If the original idea is good, usually people think it takes seven to 10 years to design a drug that will work in humans."

Dr. Sam Gandy, chairman of the Alzheimer's Association's National Medical and Scientific Advisory Council, said he was impressed by the quality of the new research, but he cautioned that similar kinds of findings have turned out to be "flashes in the pan."

The research "dovetails nicely" with existing knowledge regarding calcium and the degeneration of the brain, Gandy said. Ultimately, however, the true impact of the CALMH1 gene discovery will depend on future genetic research, he said.

In another development involving Alzheimer's research, scientists reported this week that studies with mice have helped them gain more knowledge into how a component of protein plaques appears to be directly related to the disease in some cases, but not in others.

The findings could help scientists gain greater understanding into why some people -- but not all -- who have plaques in brain tissue appear to have symptoms of the disease.

More information

Learn more about Alzheimer's from the Alzheimer's Association.

SOURCES: Philippe Marambaud, Ph.D., assistant professor of pathology, Albert Einstein College of Medicine, New York City; Sam Gandy, M.D., Ph.D., chair, National Medical and Scientific Advisory Council, Alzheimer's Association, and professor of Alzheimer's disease research, Mount Sinai School of Medicine, New York City; June 27, 2008, Cell

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