Classic CJD is a human prion disease. It is a neurodegenerative disorder with characteristic clinical and diagnostic features. This disease is rapidly progressive and always fatal. Infection with this disease leads to death usually within 1 year of onset of illness.
Creutzfeldt-Jakob disease (CJD) is a rapidly progressive, invariably fatal neurodegenerative disorder believed to be caused by an abnormal isoform of a cellular glycoprotein known as the prion protein. CJD occurs worldwide and the estimated annual incidence in many countries, including the United States, has been reported to be about one case per million population.
The vast majority of CJD patients usually die within 1 year of illness onset. CJD is classified as a transmissible spongiform encephalopathy (TSE) along with other prion diseases that occur in humans and animals. In about 85% of patients, CJD occurs as a sporadic disease with no recognizable pattern of transmission. A smaller proportion of patients (5 to 15%) develop CJD because of inherited mutations of the prion protein gene. These inherited forms include Gerstmann-Straussler-Scheinker syndrome and fatal familial insomnia.
Physicians suspect a diagnosis of CJD on the basis of the typical signs and symptoms and progression of the disease. In most CJD patients, the presence of 14-3-3 protein in the cerebrospinal fluid and/or a typical electroencephalogram (EEG) pattern, both of which are believed to be diagnostic for CJD, have been reported. However, a confirmatory diagnosis of CJD requires neuropathologic and/or immunodiagnostic testing of brain tissue obtained either at biopsy or autopsy.