GAPDH and Alzheimer disease: GAPDH is one of the very small number of human proteins previously reported to undergo DHAA modification;12 while CRMP2, like Tau, is a hyperphosphorylated, NFT-forming microtubule-associated protein.3 Quantitative analysis of the relative abundance in AD compared with control specimens is shown in the volcano plot in Fig. 4A for all phosphorylation, DHAA, and DHAA-conjugate modifications.