about 20,000 of whom had Alzheimer's and the rest of whom were cognitively normal, says lead author Gerard Schellenberg, professor in the Department of Pathology and Laboratory Medicine at the University of Pennsylvania School of Medicine, in Philadelphia.The research was conducted with scientists from 44 other universities and research institutes in the USA, a group called the Alzheimer's Disease Genetics Consortium. The consortium also helped identify a fifth gene, reported in the second study by investigators from the USA, the United Kingdom, France and other European countries."I've been in Alzheimer's genetics since 1985, and I would have to say this is the most exciting event that's happened," Schellenberg says. "Up until this point, there have only been five known genes for Alzheimer's risk, and so we've essentially doubled the genes people know about."Each new gene becomes a new clue as to what causes Alzheimer's, he says. The researchers hope the findings will help scientists create new drugs and identify high-risk individuals who don't yet show symptoms."The brain is like a black box. You can do some imaging when patients are alive, and poke around after someone dies, to try to figure out why someone has Alzheimer's or not," but this helps increase the ability to predict who will get it, he says.Current treatments are limited and there is no prevention or cure for the brain-wasting condition, says William Thies, the Alzheimer's Association's chief medical and scientific officer.The new research offers hope, experts in the field say."This was a huge and expensive undertaking, and the scope was unprecedented," says Scott Turner, director of the Memory Disorders Program at Georgetown University Medical Center. "It will give us further insight into disease mechanisms."It will still be a while before the public can benefit from the discovery. "This is very basic science ... but it is several steps away from a clinically meaningful breakthrough. The genes may in some way be associated with the disease, but what do they do?" says Alzheimer's expert Gary Kennedy, director of the Division of Geriatric Psychiatry at Montefiore Medical Center in the Bronx, N.Y.The author of the second study, David Bennett, director of the Rush Alzheimer's Disease Center at Rush University Medical Center in Chicago, concurs: "This is just kind of a first step in understanding the biology of what causes the disease," he says. "There's a whole cascade of work that needs to be done."Many of the Alzheimer's genetics researchers involved in these studies are coming together for an even larger, similar study, Schellenberg says. It is called the International Genomics of Alzheimer's Project; its members met for the first time in November in Paris.
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