The main observations were as follows: the group with Alzheimer’s disease biomarkers (versus normal AD biomarkers) were on average older, with higher WML volume, lower cognitive scores, higher Framingham stroke scores, and a higher frequency of APOE4 carriers; the Alzheimer’s pathologic change group was similar to the normal AD biomarker group in respect to mean age and cognition, and family history frequency, but showed elevated WML volume and a higher frequency of APOE4 carriers that was more consistent with AD pathology. This evidence concerns the gene APOE and early-onset autosomal dominant Alzheimer disease.