Researchers say two studies of more than 50,000 people leave little doubt that people with the five genes are more likely to develop the disease. The genes also reveal information about the disease's progress.
Scientists say the discovery may lead to ways to delay the onset of Alzheimer's disease or to slow its progress.
Researchers stress a cure for Alzheimer's is still a ways off, but this new information could prove critical in reaching that goal.
The studies are published in the journal Nature Genetics.