MAPT and Creutzfeldt Jacob disease: The total tau (t-tau) and phospho-tau (p-tau) levels, along with the p/t-tau ratio have also been suggested as clinically useful diagnostic markers [18,19]; however, these CSF biomarkers have not shown significantly high sensitivity or specificity in our experience with Korean patients with CJD, which is a major limitation of these biomarkers for this population.