25B. Creutzfeldt-Jakob disease (CJD)

Page created on June 3, 2021. Last updated on April 2, 2022 at 16:30

Definition and epidemiology

Creutzfeldt-Jakob disease is a prion disease of the brain. This disease is characterised by a long incubation period, progressive dementia, neurological deficits, and is always fatal. Transmission may be by direct contact with infected nervous tissue or blood. Confirmation is by pathological examination of the brain.

There are multiple types:

  • Sporadic CJD (90% of cases) – due to sporadic mutations in the PRNP gene
  • Familial CJD – due to familial mutations in the PRNP gene
  • Variant CJD – due to consumption of meat infected with prions

It is very rare (1/1 000 000) and a 100% mortality. Most die within a year.


CJD occurs due to a misfolded protein called PrP, also called prion protein. Normal prion proteins are in the PrPC conformation, but prion proteins in the PrPSc conformation cause other proteins in PrPC conformation to change to PrPSc. These PrPSc proteins accumulate and cause neuron death.

Clinical features

The typical features are rapidly progressive dementia, myoclonus, and cerebellar symptoms, although any neurological symptom may occur.

Diagnosis and evaluation

EEG shows periodic generalised sharp complexes. MRI may show cortical diffusion alterations. Elevated levels of the protein 14-3-3 and tau is present in the CSF.

A definite diagnosis can only be made by autopsy, which shows the spongy degeneration of the brain and deposition of prion proteins.


No treatment is available.

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