Contrary to our hypothesis, there were no differences between individuals with and without preclinical AD pathology, in groups with high NfL level or low NfL level, except that individuals with high NfL levels and preclinical AD (pathologic amyloid and tau concentrations) performed worse in the memory test Delayed recall, and those with Ng and amyloid pathology performed worse in the MMSE. This evidence concerns the gene NEFL and Alzheimer disease.