An autopsied case of Creutzfeldt-Jakob disease is reported. A 79-year-old Japanese female showed extrapyramidal sign (resting tremor, and rigidity) and dementia. She developed myoclonus and became akinetic within one year from the onset, and then died of pneumonia at age of 81. None of the members of her family had neuromuscular disorders. CT and MRI studies revealed progressive brain atrophy. Consecutive study of EEG did not reveal periodic synchronous discharges (PSD). Codon 129 polymorphism (Met/Val) and codon 180 point mutation (Val/Ile) were detected. The autopsy revealed spongiform change of cerebral cortex and negative Kuru plaques, confirming the diagnosis of Creutzfeldt-Jakob disease. Immunohistochemical study revealed weak synaptic prion staining. Western blot analysis showed positive Proteinase K resistant prion protein. Gene analysis of autopsied brain showed the same prion DNA polymorphism and mutation. The combination of codon 129 polymorphism and 180 point mutation might associate with an atypical clinical form of CJD, which shows the extrapyramidal signs at the onset, and negative PSD in EEG.