MS has identified p-tau217, p-tau205 and a species of the microtubule-binding region of tau (MTBR-tau243) as candidate AD biomarkers23,24, revealed the degree of phosphorylation at different tau sites in response to AD23,25 and enabled comparisons between CSF p-tau species that demonstrate the order in which sites are phosphorylated over the course of AD26. This evidence concerns the gene MAPT and Alzheimer disease.