The list of specific genes associated with Alzheimer's disease has gained 11 new entries. In the largest-ever genetic analysis of the condition, researchers have doubled the number of culpable gene variants by examining the DNA material of 74,076 older volunteers from all over the world. The results may set the stage for more sophisticated therapies and screening protocols. 

Published in the journal Nature Genetics, the new study is part of the International Genomic Alzheimer Project, a new comprehensive research effort comprised of four teams from the U.S. and Europe. The goal of the project is to illuminate subtle gene variants associated with late-onset Alzheimer’s, which is currently the most commonly diagnosed variant of the condition. According to the U.S. Centers for Disease Control and Prevention (CDC), up to 50 percent of Americans aged 85 and older exhibit some sign of the late-onset Alzheimer’s. 

Co-author Gerard Schelleberg of the University of Pennsylvania’s Alzheimer’s Disease Genetics Consortium told reporters that the new list of genetic variations may have a  tremendous impact on future research and drug therapy. “Not all are good drug targets,” he said of the 11 new genes. “But the longer the list of genes that you know are implicated in a disease, the more likely you are to find one that might be a good candidate for a drug.”

In addition to the 11 gene variants, Schellenberg and his colleagues found 13 variants that warrant further research. Should these prove to be relevant to Alzheimer’s disease, the list of genes associated with the condition will have grown from one to 35 in just five years. However, it may take up to 15 years to develop new therapies based on the list. 

Speaking to The Washington Post, Marilyn Miller of the organization Genetics of Alzheimer’s Disease said that exhaustive efforts like the International Genomic Alzheimer Project may represent the future of dementia and Alzheimer’s research. “Alzheimer’s is obviously a complex disease,” she said. “And because it is so complex it is only because of this broadbased collaborative effort that we’ve been able to begin to find potential solutions to tackle the disease.”

The new study adds to the growing number of research projects designed to map all genetic variations associated with a particular medical condition. Another example is the National Institutes of Health’s (NIH) Cancer Genome Atlas Pan-Cancer Effort, which seeks to compile all mutations that drive tumor growth within the body. For both cancer and Alzheimer’s disease, such genetic indices could revolutionize both drug therapies and screening practices. 

Source: Jean-Charles Lambert, Carla A Ibrahim-Verbaas, Denise Harold, Adam C Naj, Rebecca Sims, Céline Bellenguez, Gyungah Jun, Anita L DeStefano, Joshua C Bis, Gary W Beecham, Benjamin Grenier-Boley, Giancarlo Russo, Tricia A Thornton-Wells, Nicola Jones, Albert V Smith, Vincent Chouraki, Charlene Thomas, M Arfan Ikram, Diana Zelenika, Badri N Vardarajan, Yoichiro Kamatani, Chiao-Feng Lin, Amy Gerrish, Helena Schmidt, Brian Kunkle. Meta-analysis of 74,046 individuals identifies 11 new susceptibility loci for Alzheimer's disease. Nature Genetics. 2013.