McAvoy et al.6 developedthe first quantitative method for analysis of tau in CSF by mass spectrometry.Barthelemy et al. proposed a method for monitoring tau peptides inCSF using liquid chromatography-high resolution mass spectrometry.7 Recently, this approach was applied to an analysisof CSF from AD patients at mild to moderate stages and non-AD subjects.Higher tau phosphorylation rates in AD patients were observed. This evidence concerns the gene MAPT and Alzheimer disease.