By contrast, the diagnostic performance of CSF tests for CJD (RT-QuIC assays and T-tau level greater than 1149 pg/mL) and stereotyped signal anomalies on MRI was high, consistent with prior publications.15,22 Indeed, the combination of RT-QuIC, T-tau level greater than 1149 pg/mL, and stereotyped MRI findings identified all but 3 patients (97%) with CJD in this series. This evidence concerns the gene MAPT and Creutzfeldt Jacob disease.