Longevity & AgingBrain Glucose Metabolism Is Lower in Down Syndrome Two Decades Before Alzheimer's Symptoms
Researchers compared brain glucose metabolism, measured by FDG-PET, in people with Down syndrome (DS) and in people with autosomal dominant Alzheimer's disease (ADAD). Both are genetic forms of Alzheimer's. The study included 76 adults with DS, 297 ADAD mutation carriers and 188 neurotypical familial controls. Adults with DS had lower FDG uptake than controls about 20 years before expected symptom onset, even when cognitively stable. In ADAD, uptake stayed similar to controls until about 7 years before onset. Higher amyloid was linked to lower glucose metabolism in both groups, and amyloid-positive people in each group declined at similar rates. The authors conclude that FDG patterns differ between the two genetic forms, so the diagnostic use of FDG-PET depends on the type of Alzheimer's.
