The APOE ε4 allele is associated with increased frontally mediated neurobehavioral symptoms in amnestic MCI

Comorbidity Genes of Alzheimer's Disease and Type 2 Diabetes Associated with Memory and Cognitive Function

Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) are comorbidities that result from the sharing of common genes. The molecular background of comorbidities can provide clues for the development of treatment and management strategies. Here, the common genes involved in the development of the two diseases and in memory and cognitive function are reviewed. Network clustering based on protein-protein interaction network identified tightly connected gene clusters that have an impact on memory and cognition among the comorbidity genes of AD and T2DM. Genes with functional implications were intensively reviewed and relevant evidence summarized. Gene information will be useful in the discovery of biomarkers and the identification of tentative therapeutic targets for AD and T2DM.

Associations of APOE ε4 With Health and Financial Literacy Among Community-Based Older Adults Without Dementia

Objectives

Older adults often exhibit low health and financial literacy, but the reasons why remain unclear. One possibility is that those older adults at high risk for developing dementia demonstrate low literacy even in the absence of marked cognitive impairment. We therefore examined associations of health and financial literacy with the APOE ε4 allele, the chief genetic risk factor for Alzheimer's disease, among older adults without dementia.

Method

Participants were 487 older adults without dementia enrolled in the Rush Memory and Aging Project (mean age = 83, mean years of education = 15, 77% female, 91% non-Hispanic White). Participants underwent APOE genotyping and assessments of cognition, health literacy, and financial literacy. Health and financial literacy scores were also averaged into a total literacy score.

Results

ε4 was associated with lower total and health literacy, with a trend toward an association with lower financial literacy, after adjustment for age, sex, and education. Associations of ε4 with lower total and health literacy persisted after further adjustment for global cognitive function and 5 specific cognitive domains.

Discussion

ε4 affects literacy even in the absence of clinical dementia and does so relatively independent of performance on traditional cognitive tests.

Disrupted Brain Structural Connectivity: Pathological Interactions Between Genetic APOE ε4 Status and Developed MCI Condition

The ε4 allele of the apolipoprotein E (APOE) gene and mild cognitive impairment (MCI) are both risk factors for Alzheimer's disease (AD). One factor is genetic, and the other is a developed condition during the aging process. The current study intended to discover the interactions of these two factors, which may be useful in the construction of a sensitive biomarker for early identification and intervention. Eight hundred eighty-five Chinese Han ethnic subjects (aged 55 and older) completed neuropsychological tests and APOE genotyping. One hundred ten of these participants underwent magnetic resonance imaging (MRI) for T1 structural and diffusion tensor imaging scans. Subjects were divided into four groups according to APOE ε4 carrying status and MCI condition: ε4+ MCI, ε4+ normal cognition (NC), ε4- MCI, and ε4- NC. In the studied Han population in Beijing, 16.9 % (ε2ε4 = 1.1 %, ε3ε4 = 14.8 %, and ε4ε4 = 0.9 %) carried at least one ε4 allele. Significant interactions between APOE ε4 and MCI were found in general cognitive function (p = 0.001) and white matter connectivity network (clustering coefficient, p = 0.004, and local efficiency, p = 0.011); the combination of ε4 positivity and MCI was accompanied by reductions in Mini-Mental Status Examination (MMSE) scores, global white matter network connectivity, and the right hippocampus (rHIP) nodal efficiency within that network (false discovery rate (FDR), p < 0.05). Our results suggest the presence of a genetic risk and MCI led to more severe pathological symptoms and could be informative in the implementation of clinical trials for early stages of AD.