Apolipoprotein E (APOE) genotype, which strongly influences not only the prevalence and age of onset of AD but also the prevalence of amyloid angiopathy, did not show significant proportional group differences for the possession of an ε4 or ε2 allele, although the United States PSEN1 and sEOAD groups had 1.6- and 1.8-fold greater ε4 possession as compared to the Colombian PSEN1 group (Table 2). This evidence concerns the gene APOE and Alzheimer disease.