Two new studies involving a newly identified gene show that Alzheimer’s disease could be diagnosed as much as 20 years before symptoms develop. The studies by Dr. Mark Sager, professor of medicine, UW School of Medicine and Public Health (SMPH) and director of the Wisconsin Alzheimer’s Institute, and Sterling Johnson, SMPH associate professor of medicine and researcher at the Geriatric Research Education and Clinical Center at the Madison VA Hospital, were presented at the International Conference on Alzheimer’s Disease.
Sager’s study included 726 healthy, middle-aged people with a family history of Alzheimer’s disease. All carried both the newly identified gene (TOMM40) and APOE, a well-established risk gene for Alzheimer’s. Researchers discovered that 229 people with the high-risk version of TOMM40 did significantly worse on tests of learning and memory than study participants with the low-risk version.
“The deficits shown by the high-risk group are similar to the kinds of changes in memory and learning that are seen in very early Alzheimer’s,” Sager said. “In this study population, TOMM40 genotyping allowed us to find evidence of very early Alzheimer’s disease at least 20 years before any outward symptoms would be noticed.”
Johnson found that healthy, middle-aged adults who have the high-risk version of TOMM40 had a significantly lower volume of gray matter in two brain regions affected in early Alzheimer’s. Johnson says the finding in the brain’s posterior cingulate could represent a “neuro signature” for Alzheimer’s disease.
Study participants came from the Wisconsin Registry for Alzheimer’s Prevention, the largest pool of middle-aged, asymptomatic adults with a family history of the disease. Visit www.wai.wisc.edu. for more information.