MAPT and Alzheimer disease: Reviewing iron’s relationships with Aβ and tau pathologies separately, although functional studies have demonstrated the ability of high levels of iron to induce alterations in Aβ, inconsistent but existing reports of iron level indifferences between MCI and age-matched controls and the lack of—or negative—correlation between regional iron and Aβ levels in patient MRI observations suggest that iron deposition may not occur prior to or be in a linear relationship with amyloid deposition in AD progression.