Tobias Skillbäck is the first author on a paper about cerebrospinal fluid (CSF) biomarkers for Creutzfeld-Jakob disease (CJD) that we recently published in JAMA Neurology. You can read the abstract here and interviews with Tobias here and here.

CJD is a rare rapidly progressive dementia, which often lead to death within a year from symptom onset. It is characterized by the accumulation of a specific protein, the prion protein. This protein exists normally in the brain, but in the disease it undergoes a conformational change, which makes it harmful to neurons.

Spongiform brain changes (tiny holes where nerve cells have died) in CJD

Previous studies have found that CJD patients have increased CSF levels of the neuronal protein tau, probably reflecting leakage from injured neurons. CSF tau may be increased in other dementias also, for example in Alzheimer's disease. However, in contrast to Alzheimer's disease, CJD does not increase CSF levels of phosphorylated tau. Comparing levels of CSF total tau and phosphorylated tau may therefore be used to differentiate between CJD and other dementias.

The unique approach in Tobias' study was to combine clinical CSF data with information about clinical diagnoses from the Swedish Mortality registry. This identified 9765 deceased individuals with CSF data, 93 of them with CJD as cause-of-death. The project would probably not have been possible to perform in many countries (for example the United States), since it relies on the existence of a unique personal identification number, enabling cross-reference between registries.

We found that these dementia biomarkers have very high diagnostic performance for CJD. This may be useful in clinical settings, to help diagnose this disease. If a treatment is ever developed for CJD, these biomarkers may be part of the algorithm used to determine if a patient with rapidly progressive dementia should receive CJD-specific treatment.