Creutzfeldt-Jakob disease (CJD) is a rare and rapidly progressive neurological disorder. This study aims to describe and summarize the key features of CJD by looking back at medical records of patients who were diagnosed with CJD at our hospital. The researchers will collect information from routine clinical evaluations, including patients' symptoms, blood tests, cerebrospinal fluid analysis, brain imaging (such as MRI and PET), and electroencephalography (EEG). By analyzing these data together, the study hopes to provide a clearer picture of how CJD presents in routine clinical practice. This may help doctors recognize the disease more quickly in the future. No new tests or treatments will be given to patients. All data are collected from existing medical records.