MAPT and Alzheimer disease: Genetic variability in the receptors for GLP-1 (GLP-1R rs10305420, GLP-1R rs6923761) and GIP (GIPR rs1800437) has been associated with increased odds of AD and PD while correlating with elevated disease biomarkers (ie, amyloid-beta (Aβ) peptide 42, tau proteins clustered in neurofibrillary tangles (NFT)) measured in the cerebrospinal fluid (CSF).19