Apolipoprotein E E4 Allele and Risk of Dementia

Abstract

In Reply. —The clinical diagnosis of vascular dementia is a matter of considerable debate. The ratio between AD and vascular dementia cases in pathological series ranges from 2.4:1 to 4.9:1. 1 This ratio in our consecutive series is 4.6:1, indicating that vascular dementia was not overdiagnosed. Furthermore, the effect of E4 on age of onset, which we found in familial and sporadic late-onset AD, was not present in vascular dementia cases. Finally, other authors found similar frequencies of E4 in multiinfarct and AD patients. 2 However, we agree with Dr Roses and colleagues and Dr Pirttila and colleagues that the issue will be settled only by neuropathological studies. Furthermore, the following observations on illness history of the sporadic late-onset AD patients reported in our original letter, as well as of some new cases, suggest that magnitude of association of E4 with the disease, and perhaps its biologic meaning, should be