U.S. scientists have identified a gene that may raise the risk of getting Alzheimer's disease by at least 45 percent, media reported Thursday.

The gene appears to hamper a brain cell's ability to take in calcium, and if drugs can be found to reverse its effect, they may be useful in fighting Alzheimer's, researchers said.

Most cases of Alzheimer's occur in people after 65. Until now, only one gene has been identified as a likely culprit -- ApoE4. The gene proposed in the present study was dubbed the newly isolated gene CALHM1.

"What we found is that risk is completely independent from ApoE4, but it is possible for someone to be affected by both," said Philippe Marambaud, a researcher with the Feinstein Institute for Medical Research in Manhasset.

Alzheimer's is a major public health concern that will worsen unless steps are taken now to understand its myriad causes. Dozens of other genes are also under study as possibly affecting risk of the disease.

Currently, 4 million people in the U.S. have Alzheimer's, which doctors describe as progressive and irreversible, characterized by a decline in cognitive, behavioral and physical abilities.

(Agencies via Xinhua June 27, 2008)