Apolipoprotein E ε4 Allele Is Associated with Increased Atrophy in Progressive Mild Cognitive Impairment: A Voxel-Based Morphometric StudyHämäläinen A. · Grau-Olivares M. · Tervo S. · Niskanen E. · Pennanen C. · Huuskonen J. · Kivipelto M. · Hänninen T. · Tapiola M. · Vanhanen M. · Hallikainen M. · Helkala E.-L. · Nissinen A. · Vanninen R.L. · Soininen H.
aDepartment of Neuroscience and Neurology, University of Kuopio and Brain Research Unit, Clinical Research Center, Mediteknia, Departments of bPhysics and cPublic Health, University of Kuopio, Departments of dNeurology and eClinical Radiology, Kuopio University Hospital, Kuopio, and fNational Institute of Public Health, Helsinki, Finland; gDepartment of Psychiatry and Clinical Psychobiology, University of Barcelona, Barcelona, Spain
Background: The apolipoprotein E (APOE) ε4 allele is a risk factor for Alzheimer’s disease. Earlier studies have shown differences in brain structure according to the APOE ε4 status. Objective: To assess possible differences in brain structure according to the APOE ε4 status in mild cognitive impairment (MCI) subjects in relation to conversion to dementia. Methods: In a follow-up study of 56 MCI subjects, 13 MCI subjects progressed to dementia (PMCI) during a mean follow-up time of 31 months. Brain structure differences in both stable MCI (SMCI) and PMCI ε4 carriers and noncarriers in the baseline MRI scan were assessed with voxel-based morphometry. Results: The SMCI ε4 carriers had atrophy in the amygdala and hippocampus compared to the SMCI noncarriers. The PMCI ε4 carriers revealed atrophy of the left inferior frontal gyrus and parietal cortex compared to the PMCI noncarriers. Conclusion: The rate of brain atrophy in certain brain areas may be increased in ε4-positive MCI subjects progressing to dementia.