Researchers have detected more genes associated with an increased risk of developing Alzheimer’s disease, the most common cause of dementia. Researchers at Massachusetts General Hospital and Harvard Medical School have identified four novel genes that may significantly influence risk for the most common late-onset form of the Alzheimer’s disease.

According to the report appearing online today in the American Journal of Human Genetics, researchers with the Alzheimer’s Genome Project have used a family-based genome-wide association approach to evaluate the activity of all human genes among families with patients with Alzheimer’s disease and to compare the results with those from families whose members had not been affected by the disease.

These samples were collected from individuals of European descent since 1999 as part of the National Institute of Mental Health Genetics Initiative Study, the researchers said.

Until now, only one gene had been identified as a likely culprit –APOE4. The researchers found the strongest association between Alzheimer’s age-of-onset and a novel chromosome 14 gene, a gene that is also in the vicinity of the presenilin-1 gene, which is an early-onset Alzheimer’s disease gene.

“The genetic association of Alzheimer’s with this novel chromosome 14 gene, which like APOE appears to influence age of onset, is sufficiently strong to warrant intensive follow-up investigations into its role in the process of nerve cell death in this disease,” said Rudolph Tanzi, PhD, director of the MGH-MIND Genetics and Aging Research Unit, who led the study.

According to the World Health Organization, there are about 18 million people with Alzheimer’s, worldwide. There is no cure for Alzheimer’s disease. Current drugs can delay the symptoms slightly, but cannot cure it. Late-onset Alzheimer’s disease accounts for about 95 percent of all cases.