MAPT and Creutzfeldt Jacob disease: The CSF concentration of ubiquitin has been shown to be significantly increased in CJD,30, 31, 32 another disease characterized by high CSF T‐tau concentration.60 The CSF concentrations of T‐tau is considered to reflect neuronal and axonal degeneration,61 while P‐tau181 has been found to correlate with tangle load in the brain.62 T‐tau has been suggested to reflect the intensity of neurodegeneration and to predict progression rate.63, 64, 65 We identified a strong correlation between CSF ubiquitin and T‐tau, which supports ubiquitin to also reflect neuronal and axonal degeneration.