MAPT and early-onset autosomal dominant Alzheimer disease: Numerous studies have identified reductions in melatonin in Alzheimer’s disease,4-10 and melatonin has been shown to efficiently attenuate tau hyperphosphorylation.98 As women exhibit significantly higher melatonin amplitudes than men,99 lower melatonin levels in men may impact circadian rhythms and exacerbate tau neuropathology.