The large-scale study has more than doubled the number of known Alzheimer's susceptibility genes to 21. The research, reported in the journal Nature Genetics, also identified another 13 possible risk genes for further analysis.
Dr Gerard Schellenberg, one of the leading researchers from the International Genomics of Alzheimer's Project, said: 'Here we greatly increased the list of possible drug target candidates for Alzheimer's disease, finding as many new significant genes in this one study as have been found in the last 15 years combined. This international effort has given us new clues into the steps leading to and accelerating Alzheimer's disease'.
By pooling together previously studied and newly collected DNA data from a total of 25,500 Alzheimer's disease patients and 49,038 controls, researchers found changes in DNA that were more common in patients with the disease.
The genes linked to Alzheimer's risk are involved in a number of different cellular pathways. The most significant association was found in a region that plays a role in the immune system and inflammatory response, and is also associated with a risk of multiple sclerosis and Parkinson's disease.
This work confirms the complexity of Alzheimer's disease, but it may allow researchers to better understand the causes of the disease, which could then be used to develop better treatments.
Dr Margaret Pericak-Vance, a lead researcher based at the University of Miami, said: 'The discovery of novel pathways is very encouraging considering the limited success of Alzheimer's disease drugs tested so far. Our findings bring us closer toward identifying new drug targets for Alzheimer's and other neurodegenerative diseases'.
Despite the results being promising, researchers were also keen to point out that more work needs to be done.
Dr Schellenberg said: 'Alzheimer's is a complex disorder, and more study is needed to determine the relative role each of these genetic factors may play'.
Dr Julie Williams from Cardiff University led the work in the UK. Speaking to the Daily Mail, she agreed that the findings need to be followed up with 'great urgency' to determine exactly how the genes cause dementia. She added: 'I do think that in ten years' time we might be looking at a genetic therapy. That might be feasible but not quite yet'.