GAP43 and early-onset autosomal dominant Alzheimer disease: Additionally, we examined whether Alzheimer’s disease pathology moderated these relationships by stratifying older adults into no Alzheimer’s disease pathology, SNAP and Alzheimer’s disease continuum groups using the AT(N) framework.3 In the current study, across all older adults, biomarkers of neuronal dysfunction (plasma NfL and CSF GAP-43) had the highest relative importance metrics for episodic memory performance after adjusting for control variables.