Investigating Gene Expression Patterns in Dementia Patients: A Potential Early Biomarker for Alzheimer’s Disease

Dementia is a severe neurodegenerative disorder commonly found in adults over 70 years of age. Alzheimer’s disease (AD) is the most prevalent type of dementia and currently has no therapeutic pathway able to effectively slow down or reverse progression of the disease. The insidious onset of AD manifests over 15 years and often, AD is left undiagnosed until the very end. This research aims to search for combinations of RNA-sequencing (RNAseq) gene expression patterns that can act as early biomarkers for AD. Provided by the Allen Brain Institute, this paper uses RNAseq expression values of 14 genes collected from 107 post-mortem brains in the hippocampus (HIP) and the forebrain white matter (FWM). Grouped according to dementia status, values were correlated and graphed against age, CERAD, NIA-Reagan scores and Braak stages. Qualitative deductions were initially made from bar graphs, in which, if concluded worthy of investigation, quantitative data analyses using Pearson’s correlation coefficient and T-tests were then conducted. From the obtained information, aging, dementia and brain area effects were taken and analyzed. Unexpectedly, genes with neuroprotective roles or are involved in growth of cells exhibited higher expression as age increases in dementia patients. The implications of overexpression of genes in dementia and AD may be a new topic worthy of further research for better understanding of such disorders. Additionally, majority of the notable trends were found in the FWM, the area of the brain often overlooked in research involving neurodegenerative diseases. Identification and analyses of these patterns offer means to investigate the subject from new angles. By using obtained information on potential early biomarkers to form parameters for larger and more advanced studies in this field, developing a full-fledged clinical practice for early diagnosis of AD seems attainable.