Comprehensive Clinical Overview of Early-Onset Parkinson Disease: Pathophysiology, Diagnosis, Management, and Emerging Evidence
1. Definition, Epidemiology, and Classification Parkinson disease (PD) is a progressive, proteinopathic neurodegenerative disorder characterized by the selective loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the presence of intraneuronal α-synuclein aggregates—referred to as Lewy bodies—fulfilling the neuropathological criteria of synucleinopathy. The classic motor triad—bradykinesia, rigidity, and resting tremor—requires the presence…
