Two studies indicate that some of the pathologic changes associated with Alzheimer's disease in older individuals are not apparent in young people who carry the apolipoprotein (APOE) genetic risk factor for developing the disease. In the first study, no differences were found in hippocampal volume or asymmetry between cognitively normal adolescent carriers and non-carriers of the ApoE ɛ4 or ɛ2 allelles. The second study reports no differences in plasma concentrations of amyloid-β peptides among young adult ɛ4, ɛ3 or ɛ2 carriers.