Neuropathological epidemiology of cerebral aging: a study of two genetic polymorphisms.

Abstract

We studied whether ApoE and -219 GT (ApoE promoter) polymorphism modulates neurofibrillary tangle (NFT) and senile plaque (SP) development in aging among 190 non-institutionalized individuals (mean age 79.5 years). Analysis revealed that the mean Braak stage was higher in epsilon4 allele carriers. Once individuals with Braak stage V were excluded (n = 5), relationships between NFT and the two genotypes studied were weak, whereas in epsilon4 allele carriers, the risk of SP was multiplied by 4 to 7 in four areas (CA1, subiculum, isocortex and entorhinal cortex). This association was more pronounced in subjects under 80 years and was also observed when analysis was restricted to Braak stages 0, I and II. Epsilon 2 allele carriers appeared to have fewer lesions but, due to limited numbers, this trend was not significant. In two regions (CA1, subiculum), the number of SP increased significantly for individuals who were homozygous for the T allele of -219 GT. However the association was no longer significant when controlling for ApoE epsilon4. It should be noted that the brain of elderly subjects carrying one epsilon4 allele may not undergo senile changes.