APOE and Alzheimer disease: Microtubule-associated protein tau (MAPT) rs242557 with the major allele G and the minor allele A is also related to tauopathies via differential expression of various exons relevant to tau aggregation.4‐6  MAPT rs242557 (MAPT for short) has been associated with increased risk of Ad, and there is emerging evidence for an additive effect of APOE and MAPT in modulating the risk for AD.7