Results of a recent study were released April 3, 2011 in the online issue of Nature Genetics that confirm one gene variant has been proven, and several others have been identified that may be risk factors for late-onset Alzheimer’s, the most common form of the dementia.
In the largest genome-wide association study (GWAS) ever conducted on Alzheimer’s, researchers from around the world studied and shared the DNA samples of more than 56,000 participants. They analyzed the data to detect gene variations that could produce subtle effects on the developing, or risk for developing, Alzheimer’s.
“New technologies are allowing us to look at subtle genetic differences among large groups of study participants. By comparing people diagnosed with Alzheimer’s with people free of disease symptoms, researchers are now able to discern elusive genetic factors that may contribute to risk of developing this very devastating disease,” said Richard J. Hodes, M.D., director of the National Institute on Aging (NIA). “We are entering an exciting period of discoveries in genetics that may provide new insights about novel disease pathways that can be explored for development of therapies.”
Until recently, only one gene variant had been confirmed as a significant risk factor gene for the common form of late-onset Alzheimer’s, which usually exhibits after age 60, Apolipoprotein E-e4 (APOE-e4). In 2009 and 2010, researchers confirmed additional gene variants of CR1, CLU and PICALM as possible risk factors for late-onset Alzheimer’s. This newest GWAS confirms that a fifth gene variant, BIN 1, affects development of late-onset Alzheimer’s. It also identified genetic variants significant for Alzheimer’s at EPHA 1, MS4A, CD2AP, and CD33.
The genes identified by this study could show researchers the neuro-pathways involved in inflammation, movement of proteins within brain cells, and lipid transport as being important in the disease process.
A second paper, appearing online in the journal Nature Genetics presented GWAS findings for Alzheimer’s by another scientific team. Led by Julie Williams, Ph.D. of Cardiff University School of Medicine in Wales found the same genes as risk factors and identified a additional gene variant of interest, ABCA7.
“Researchers conducting GWAS are looking for genetic variations that may have a smaller effect but still play a role in the disease,” said Gerard Schellenberg, Ph.D., University of Pennsylvania School of Medicine, Philadelphia. “Our findings bring us one step closer to a fuller understanding of the genetic basis of this complex disease, although more study is needed to determine the role these genetic factors may play in the onset and progression of Alzheimer’s.”
This is Ron White, two-time USA Memory Champion , memory training expert, and memory keynote speaker.
National Institute on Aging — Studies Find Possible New Genetic Risk Factors For Alzheimer’s Disease: http://www.nia.nih.gov/Alzheimers/ResearchInformation/NewsReleases/PR20110404GWAS.htm