Beta-amyloid accumulation in the brain is currently the most commonly accepted hypothesis for the onset of AD pathology, but findings that beta-amyloid is also found in the brain of healthy older adults and that the association between beta-amyloid load and dementia symptoms lessens with age support the contribution of other factors, such as tau accumulation, inflammation, as well as metabolic and cardiovascular factors (106, 112). This evidence concerns the gene MAPT and Alzheimer disease.