Penn researchers lead discovery of four new Alzheimer’s genes

Researchers have discovered four new genes that increase the risk of acquiring Alzheimer’s, a degenerative disease that affects one in eight Americans over age 65.

University of Pennsylvania professor of pathology Gerard Schellenberg coordinated the analysis of genetic samples from more than 50,000 people in the United States and Europe. The more genes known to contribute to Alzheimer’s, Shellenberg said, the better chance of developing a drug to treat the disease.

“Probably not every one of these would be a drug discovery target,” Schellenberg said. “But the more genes you know and the more new pathways you have, the more chance you’ll say ‘Aha! There’s where we gotta focus.’”

The discovery of the genes strengthen current theories that cholesterol and lipids moving around the brain have some connection to Alzheimer’s. They also suggest that the functioning of the immune system in the brain plays a role.

The discovery brings the tally of genes tied to the disease up to 10. The newly discovered genes increase the risk of acquiring the disease by a much smaller factor than APOE, the main Alzheimer’s gene discovered more than a decade ago.

“When you have one dose (of APOE) you have a four to five fold greater chance of getting Alzheimer’s,” Schellenberg said. “If you took all the other nine genes and you happen to have all the bad forms of all those nine genes, it would be roughly equivalent to a four-fold increase.”

The genes will likely not be used in predictive tests for patients, said Dr. Ausim Azizi, head of neurology at Temple University School of Medicine.

“In the long run, though, it’s going to be one of those genes that contributes to our understanding of how the genetic factors plays in,” Azizi said.