For instance, the A allele of rs242557 has been linked to increased plasma tau levels and enhanced transcriptional activity of the MAPT promoter, indicating a regulatory role in gene expression [22] Similarly, rs3785883 has been associated with higher cerebrospinal fluid (CSF) tau concentrations and accelerated functional decline in patients with Alzheimer’s disease, suggesting a broader role in tau-related neurodegeneration [23]. This evidence concerns the gene MAPT and Alzheimer disease.