Overview of Alzheimer's and Parkinson's diseases and the role of protein aggregation in these neurodegenerative diseases

Alzheimer’s disease (AD) and Parkinson’s disease (PD) are the two most common neurodegenerative diseases, and together they affect approximately 56 million people worldwide. Despite distinct clinical features and the involvement of relatively disparate neural systems, both diseases are proteinopathies with significant overlap in some of the potential mechanisms of neuronal dysfunction and death. Models of protein aggregation and the relationship to disease onset and progression have widespread implications. Clearly, understanding the role protein aggregation plays in supporting or damaging cellular function is key to understanding the mechanisms of disease and developing new, effective therapies. A second application of this knowledge is to the development of relevant biomarkers of disease. Together, early identification of disease onset and the targeting of appropriate cellular pathways or polypeptides provide the best opportunity to develop disease-modifying interventions for people with neurodegenerative diseases. This chapter provides an overview of AD and PD, and it discusses current theories of the relationship between protein aggregation and neurodegeneration