Scientists have identified a gene that may raise the risk of getting the most common kind of Alzheimer's disease by about 45 percent in people who inherit a certain form of it.

That form of the gene appears to hamper a brain cell's ability to take in calcium, researchers said. If drugs can be found that reverse its effect, they may be useful in fighting Alzheimer's, researchers said.

Most cases of Alzheimer's appear after age 65. So far, only one gene has been firmly established as affecting the risk of this late-onset version. The gene proposed in the new study, called CALHM1, appears to have a much smaller impact on the disease risk.

Dozens of other genes are also under study as possibly affecting risk of the disease.

The new work appears Friday's issue of the journal Cell. The work is reported by Philippe Marambaud of the Feinstein Institute for Medical Research in Manhasset, N.Y., and others in the United States and elsewhere.

They studied the gene with data from more than 2,000 people with Alzheimer's and about 1,400 people without the disease.