MAPT and Alzheimer disease: Thedegree of hyperphosphorylation was higher for T111, T205, S208, andT217, than for T181 which is usually employed as a biomarker for AD.8 Phosphorylation on threonine 217 was identifiedin brain tissue, CSF, and plasma of patients and is considered asa new potential biomarker for AD.9,10 An LC–MSanalysis of two phosphorylated tau isoforms (pT181 and pT217) hasbeen recently reported supporting that pT217 can be a useful biomarkerof Alzheimer’s disease.11 In sarkosylinsoluble fraction of brain tissue, different phosphorylations werealso confirmed by mass spectrometry.12