In the largest-ever genetic analysis conducted on Alzheimer's disease, researchers have identified 11 new genes associated with the disorder, doubling the number of known gene variants linked to it.

The International Genomic Alzheimer's Project, a collaboration of two groups in America and two in Europe, scanned the DNA of people with and without the disease to look for gene variants involved in late-onset Alzheimer's, the most common form.

The study, which appeared Sunday in Nature Genetics, provides additional evidence of the involvement of certain genes in Alzheimer's, such as one connected to the abnormal accumulation of amyloid protein in the brain, which has been associated with the disease. It also finds new gene-related risk factors that may influence cell functions.

The identification of so many new genes offers promising new avenues to finding drug therapies, researchers said.