This finding suggests that although the MBI-apathy and non-apathy MBI groups both exhibit pathological features associated with AD, the MBI-apathy group appears to show more pronounced changes in biomarkers specifically associated with total tau pathology (i.e. neurodegeneration) and the non-apathy MBI group appears to display earlier changes primarily related to amyloid and tau phosphorylation. The gene discussed is MAPT; the disease is Alzheimer disease.