Supplementary Material for: Patterns of Cortical Thickness according to APOE Genotype in Alzheimer’s Disease

<i>Background:</i> Possession of one or more apolipoprotein E (APOE) ε4 alleles may influence the distribution of atrophy and clinical phenotype. We aimed to assess the influence of APOE genotype on cortical thickness and regional brain volumes in AD (Alzheimer’s disease).<i> Methods:</i> We included 38 patients (9 ε4 non-carriers, 23 ε4 heterozygotes, 6 ε4 homozygotes) and 23 controls. Each subject had 2 magnetic resonance imaging (MRI) scans and a neuropsychological battery. Cortical thickness and isthmus cingulate volume were measured using FreeSurfer; the volumes of the hippocampus, whole brain, and lateral ventricles were calculated using manual and semi-automated volumetry. <i>Results:</i> Compared with controls, cortical thickness was significantly lower: in the bilateral temporal, posterior parietal and occipital regions in non-carriers, in the medial temporal and left parietal regions in heterozygotes, and in the medial temporal lobe in homozygotes. Comparisons between AD subgroups did not show significant differences. A trend for larger brain and isthmus cingulate volumes and smaller hippocampal and ventricular volumes with increasing ε4 dose were seen. These differences were supported by neuropsychological profiles. <i>Conclusion:</i> These results suggest that APOE genotype may influence the topography of regional atrophy and cortical thinning in AD.

<i>背景:</i> 携带1个或多个载脂蛋白E（apolipoprotein E，APOE）ε4等位基因，可能会影响脑萎缩的分布模式与临床表型。本研究旨在评估APOE基因型对阿尔茨海默病（Alzheimer’s disease，AD）患者皮层厚度及脑区域体积的影响。
<i>方法:</i> 本研究纳入38例AD患者（9例ε4非携带者、23例ε4杂合子、6例ε4纯合子）及23例健康对照。所有受试者均接受2次磁共振成像（magnetic resonance imaging，MRI）扫描，并完成神经心理学成套测评。采用FreeSurfer软件测量皮层厚度及扣带回峡部体积；采用手动及半自动化容积分析法计算海马体、全脑及侧脑室体积。
<i>结果:</i> 与健康对照相比，ε4非携带者的双侧颞叶、后顶叶及枕叶皮层厚度显著降低；ε4杂合子的内侧颞叶及左侧顶叶皮层厚度显著降低；ε4纯合子的内侧颞叶皮层厚度显著降低。AD各亚组间未观察到显著差异。随着ε4等位基因剂量增加，全脑及扣带回峡部体积呈增大趋势，而海马体及脑室体积呈减小趋势。该结果得到了神经心理学测评结果的佐证。
<i>结论:</i> 本研究结果表明，APOE基因型可能会影响阿尔茨海默病患者脑区域萎缩及皮层变薄的分布特征。