An autopsied case of panencephalopathic‐type Creutzfeldt‐Jakob disease with mutation in the prion protein gene at codon 232 and type 1 prion protein

In this study, we describe the clinicopathologic findings in a 68‐year‐old man with panencephalopathic‐type CJD with a substitution from methionine to arginine at codon 232 (M232R) in the prion protein (PrP) gene and type 1 PrP. Initial symptoms of the patient were a rapidly progressive memory disturbance and disorientation. The patient showed myoclonus and periodic sharp‐wave complexes on electroencephalogram in the early stages of disease. Diffusion‐weighted MRI along with the presence of both neuron‐specific enolase and 14‐3‐3 protein in the CSF showed similarities to classic‐type sporadic CJD. The patient reached the akinetic mutism state 2 months following the onset of symptoms and died after 13 months. Neuropathologic examination revealed panencephalopathic‐type CJD pathology including widespread neuron loss with severe hypertrophic astrocytosis and status spongiosus in the cerebral gray matter, particularly in the neocortex. Cerebral white matter and the cerebellum also showed severe involvement. Immunohistochemical staining for PrP showed diffuse gray matter staining, indicating synaptic‐type PrP deposition without plaque‐type. Two different clinical phenotypes of M232R CJD were recognized despite the presence of the same PrP genotype, and the present case is speculated to correspond to the rapid‐type.