NMNAT2 and Alzheimer disease: The expression of NMNAT2 is downregulated in AD patients' brains (Ali et al., 2016), and caffeine (1,3,7‐trimethylxanthine) increases the expression of NMNAT2 in cortex of wild type, NMNAT2 heterozygous knockout, and rTg4510 tauopathy mice (Ali et al., 2017).