Voxel-based Morphometry And ApoE Gene Detection In The Diagnosis Of Alzheimer’s Disease

Purpose:Using voxel-based MRI morphometry and gene detection technology to analyze the characteristics of brain gray matter volume changes and ApoE gene polymorphism in a MCI and AD patients with compared with normal elderly people.Exploring the possible correlation between the above changes and the pathogenesis of a MCI and AD to provide basis for early diagnosis and early intervention of AD.Methods:Recruiting 14 cases of a MCI patients,12 cases of AD patients and 15 normal elderly people who were matched with each other by age,gender,ethnicity,education,living background and determined no blood relationship.Three-dimensional T1 WI scan with 3.0T magnetic resonance imaging.Using the SPM12-based DARTEL toolbox to preprocess the structural images obtained from the scan,and then compare voxel-based statistical results of the whole brain gray matter volume of the group a MCI,group AD and group control.Detecting the ApoE gene by drawing blood to identify the allele and genotype of the ApoE gene in each sample.The data obtained was analyzed by SPSS20.0 software to calculate the allele frequency and genotype frequency of the three groups of ApoE genes.Using Hardy-Weinberg genetic balance law to test the goodness of fit.Using the X~2 test or Fisher’s Exact Test to compare count datas.One-way analysis of variance(ANOVA)test was used to compare measurement data of multiple groups.Inspection level α=0.05,two-sided inspection.Results:1.The frequency distribution of three groups of genotypes was tested by the Hardy-Wein-Berg genetic balance law.The results showed that the genotype frequency of the three groups were in the state of genetic equilibrium(p>0.05).2.The frequency distribution of ApoE genotypes in the group AD,group a MCI and group control indicated that group a MCI and group control had the highest ratio of ApoEε3/ε3 among the three groups,followed by ApoEε3/ε4 and ApoEε2/ε3,ApoEε2/ε4,ApoEε4/ε4 and ApoEε2/ε2 genotypes were not detected.The group AD had the highest ε3/ε4 genotype frequency(75.00%),there was significant difference between group AD and group control(p < 0.05)and group control had the highestε3/ε3 genotype frequency(80.00%),which was higher than group AD(p<0.05).And the ε3/ε4 genotype in the group a MCI was significant difference between the group a MCI and the group control(p<0.05)and theε3/ε3 genotype group the control was significant difference between the group a MCI and the group control(p<0.05).3.The ApoEε4 gene frequency in the group AD was 37.50%(9/24),which was statistical difference between group AD and group control(10%,3/30)(X~2=5.83,p<0.05);the ApoEε4 gene frequency in the group a MCI was 21.43%(6/28),there was no significant difference between group a MCI and group control(X~2=1.44,p>0.05);there was no significant difference in ApoEε4 gene frequency between the group AD and group a MCI(p>0.05).Compared with the group control,the ApoEε4 gene increases the risk of AD(OR=5.400,p=0.021),and the ApoEε3 gene was not associated with AD.4.Compared with the group control,the gray matter atrophy of the group AD was mainly located in the right hippocampus,thalamus,posterior cingulate cortex,superior temporal gyrus,superior parietal lobule,caudate nucleus,superior frontal gyrus,middle frontal gyrus and bilateral insula,Inferior frontal gyrus andsuperior parietal lobule on the right side.5.Compared with the group control,the gray matter atrophy of the group a MCI was mainly located in the left insula,superior frontal gyrus,middle frontal gyrus,anterior insula,posteriorcentral gyrus,ventromedial prefrontal lobe,bilateral superior parietal lobule,right angular gyrus.6.Hippocampal atrophy was more pronounced in patients with AD who carried the ApoEε4 gene.Conclusions:1.It was confirmed that ApoEε4 was a risk factor in elderly patients with sporadic AD.2.ApoE gene polymorphism was associated with the morbidity of patients with a MCI,and ApoEε4 may be a risk factor for a MCI.3.The gray matter atrophy of in patients with AD was mainly located in the hippocampus.The thalamus,posterior cingulate cortex were also involved.Gray matter atrophy in patients with a MCI was mainly located in the parietal lobule and the insular.In addition,early recognition of hippocampus,thalamus and posterior cingulate cortex atrophy may also help early diagnosis of AD.4.Hippocampal atrophy was more pronounced in patients with AD who carried the ApoEε4 gene.