The Influence of Circadian Rhythm Disruption and APOE4 on the Prognosis and Progression of Alzheimer’s Disease

Author

• Kayla Bradby, Lynn University

Date of Award

8-19-2026

Document Type

Capstone

Granting Institution

Lynn University

Degree Name

Master of Science (M.S.)

Degree Program

Biological Sciences

Department

College of Arts and Sciences

First Advisor

Dr. Kimberly Rowland

Abstract

Alzheimer’s disease is characterized by cognitive decline and memory loss and is the most common form of dementia. Genetic factors such as apolipoprotein E have been significantly associated with AD development and progression, most specifically the APOE4 isoform. Emerging evidence has shown that when the body’s circadian rhythm, the 24-hour dark/light cycle, is disrupted, the potential to develop a neurodegenerative disease such as AD increases. The purpose of this literature review is to examine the relationship between AD, circadian rhythm, and the APOE isoforms. This review puts a particular emphasis on the APOE4 isoform, as it has been shown to have the most effect on disease development and progression. Human subjects have provided research displaying how APOE4 is associated with altered sleep/wake cycles and increased accumulation of amyloid-beta plaques. Drosophila melanogaster also provides further insight into this relationship, displaying how lipid metabolism may be altered as a result of the different APOE isoforms. Overall, the emerging and existing evidence indicates that there is a relationship between APOE4, circadian rhythm, and the development and progression of AD, although the underlying mechanisms as to why remain unclear. Continued research using both human subjects and diverse animal models may potentially help to clarify how exactly circadian rhythm disruption directly correlates with APOE4-associated AD risk and whether there could be potential prevention or treatment to stop it.

Recommended Citation

Bradby, K. (2026). The influence of circadian rhythm disruption and APOE4 on the prognosis and progression of Alzheimer’s disease [Master's capstone, Lynn University]. SPIRAL. https://spiral.lynn.edu/etds/465