Diffuse Lewy body disease without amyloid plaques in a patient homozygous for apolipoprotein E allele epsilon 4: a...

A middle-aged woman developed extrapyramidal motor symptoms, personality and behavioral changes, and rapidly progressive dementia. Apolipoprotein E genotyping revealed that she was homozygous for the epsilon 4 allele. At autopsy, there were numerous cortical and subcortical Lewy bodies but no neuritic plaques (NPs) or neurofibrillary tangles (NFTs). This case, the first explicitly reported patient homozygous for the epsilon 4 allele having dementia of the Lewy body type (DLBT) without NPs and NFTs, reinforces the distinction between DLBT and dementia of the Alzheimer type. It calls into question the pivotal role of the epsilon 4 allele in the pathogenesis of NPs and NFTs but raises the possibility of its being an independent risk factor for the development of DLBT.