Dysfunction in protein clearance mechanisms, including autophagy and the ubiquitinproteasome system, may contribute to the accumulation of misfolded proteins and the formation of Lewy bodies. Impaired clearance of damaged or aggregated proteins can overwhelm cellular defenses and lead to neuronal toxicity and degeneration. Genetic and Environmental Factors. While most cases of PD are sporadic, genetic factors contribute to disease susceptibility and may interact with environmental exposures. Mutations in genes such as SNCA (α-synuclein), LRRK2 (leucine-rich repeat kinase 2), Parkin, PINK1, and DJ-1 are associated with familial forms of PD, providing insights into disease mechanisms. Environmental factors, including pesticides, herbicides, heavy metals, and other toxins, may increase the risk of developing PD by contributing to oxidative stress, mitochondrial dysfunction, and α-synuclein aggregation. We examined the documents in the CAS Content Collection associated with the PD research from the viewpoint of their relation to the pathophysiological PD hallmarks (Figure ), as well their relative growth in the last five years (2019-2023) (Figure ). The largest portion of the PD-related documents are associated with the genetic factors for PD pathophysiology, while the mitochondrial disfunction, along with neuroinflammation and environmental factors, exhibit the fastest and steady growth.