Influence of ApoE genotype on cerebral amyloid angiopathy after closed head‐injury

Abstract

Introduction: Possession of an ε4 allele of the apolipoprotein E gene is a recognized genetic risk factor for Alzheimer's disease but has also been linked to traumatic brain injury, dementia pugilistica, cerebrovascular diseases and stroke.Materials and methods: In this study, we have combined morphological and quantitative analysis to investigate the effect of the genotype on the pathology observed after fatal closed head‐injury in a cohort of 88 patients.Results: Quantification of the amyloid‐β (Aβ) pathology in these cases has confirmed the original qualitative observations made by Nicoll et al. (Nat Medicine 1995) that the amount of Aβ pathology correlates with the ε4 gene dose. More striking, however, was the fact that the presence of cerebral amyloid angiopathy (CAA) was very strongly associated with the possession of the ε4 allele. Seven out of eight cases with CAA were ε4 carriers and half of them were ε4 homozygotes.Conclusion: Over the total HI cohort, ε4 carriers had 8.75 times more chance of developing CAA after brain trauma than non‐ε4 carriers.