An autopsy case of Creutzfeldt‐Jakob disease with a V180I mutation of the PrP gene and Alzheimer‐type pathology

We report an autopsy case of Creutzfeldt‐Jakob disease with a codon 180 point mutation of the prion protein gene (PRNP). A 77‐year‐old woman developed gait instability, followed by dementia and limb/truncal ataxia. She became akinetic and mute 18 months and died of pneumonia 26 months after the disease onset. Analysis of the PRNP gene revealed a codon 180 point mutation. Post‐mortem examination revealed marked spongiosis, neuronal loss, and astrocytic gliosis in the cerebral cortex. Mild to moderate spongiosis and neuronal loss were observed in the limbic cortex and basal ganglia. There was no spongiform change in the hippocampus, brain stem or cerebellum. Many senile plaques and neurofibrillary tangles were found, and the Braak stages were stage C and stage IV, respectively. Immunostaining for prion protein (PrP) revealed granular (synaptic‐type) and patchy PrP deposition in the cerebral cortex and especially in the hippocampus. Most patchy PrP deposits were colocalized with amyloid β plaques, but some of them were isolated. The relatively strong PrP deposition and coexistence of Alzheimer‐type pathology of this case are remarkable. We suppose that amyloid β plaques might act as a facilitating factor for PrP deposition.