Cecily O'Connor
RedwoodAge.com

A team of researchers identified an Alzheimer's gene that could lead to early diagnosis and treatment of the brain disorder, which is expected to afflict millions of baby boomers in coming years.

The newly identified gene, called GAB2, appears to increase the likelihood Alzheimer's in people who carry certain other genes, including APOE4, which is known to predispose adults over 65 to the neurological disease. As part of the study, researchers screened the DNA from 1,400 people who had been diagnosed with Alzheimer's and looked at more than 500,000 genetic "letters," or variations, to find the GAB2 gene. They believe the healthy form of this gene may prevent brain cells from developing tangles, or intracellular abnormalities. Results of the study are featured in the June 7 issue of the journal Neuron.

"The study ushers in a new era of genetics research which will help us identify the remaining genes involved in Alzheimer's," Dr. Eric Reiman, the study's first author and executive director of the Banner Alzheimer's Institute, said in an interview. New technologies will enable scientists to look at even more genetic letters and identify more genes that "contribute to up to 80 percent of the risk for developing Alzheimer's," he added.

Alzheimer's is expected to affect about 15 million Americans by 2050, up from 5 million today. The disease gradually eats away at a person's memory and ability to learn, reason, communicate and carry out daily activities. While there is no cure for Alzheimer's, the new gene discovery could facilitate development of therapeutic drugs to treat the disorder.

"Today's technologies permit us to survey a sufficient number of letters throughout the human genome to provide a clearer picture of how life works and ultimately allow better clinical management of patients," said Dr. Dietrich Stephan, the paper's senior author and director the neurogenomics division at Translational Genomics Research Institute.

Researchers used technology from Affymetrix that enabled them to produce a genetic map of each brain tissue sample and isolate the GAB2 gene.

Kronos Science Laboratory, which funded the study, is working to develop a test that helps diagnose and determine a person's genetic predisposition for developing Alzheimer's. Chris Heward, president of Kronos, said in an interview that he hopes the test will be available as early as six months from now for use in clinical trials. A Federal Drug Administration-approved test for use in the marketplace is likely several years away, he said.

Overall, a diagnostic test could delay the onset of Alzheimer's symptoms by five years, greatly reducing the number of baby boomers affected.

"All this test can do is provide a measure of one's genetic risk, and that risk can be attenuated by environmental factors," Mr. Heward said. "The more we understand how the environment and genetics work together... the better the prevention. If we can push back the age at which the first symptoms occur by five years we can cut the incidence of the disease by half."