Apolipoprotein E polymorphism influences the cerebral metabolic pattern in Alzheimer's disease

Abstract

In 49 patients with the clinical diagnosis of probable Alzheimer's disease (AD) apoE genotyping as well as regional cerebral glucose metabolism (rCMRGl) using positron emission tomography (PET) of [ 18F]2-fluoro-2-deoxy- d-glucose (FDG) were studied. The metabolic pattern was condensed to a ratio by dividing the rCMRGl of typically affected regions (temporo-parietal and frontal association cortex) by the rCMRGl of the least affected regions (primary cortical areas, basal ganglia, cerebellum and brainstem). ϵ4-Heterozygotes and ϵ4-homozygotes were grouped together, and also those lacking the ϵ4-allele (non- ϵ4). For the metabolic pattern we found a significant correlation to severity of dementia in both groups ( ϵ4: r=0.49, P=0.05; non- ϵ4: r=0.59, P=0.006). On ANCOVA severity of dementia and ϵ4 status were independent predictors of the cerebral metabolic pattern ( P=0.01). These differences may be attributed to ϵ4 dependent histopathologic changes.