MAPT and Alzheimer disease: The Enzyme Linked Immunosorbent Assay technology was used to detect GAP-43 in human cerebrospinal fluid, and GAP-43 showed a high level of expression in the cerebrospinal fluid of AD patients, which was consistent with the changes of T-tau and P-tau.[31] Compared with other neurodegenerative diseases, GAP-43 is more obvious in the cerebrospinal fluid of AD, and it is one of the specific biomarkers of AD.