This observational study aims to systematically characterize a cohort of patients with early-stage Parkinson's disease (PD) attending the Movement Disorders Center of AUSL-IRCCS Reggio Emilia, Italy. PD is the second most common neurodegenerative disorder, affecting about 1% of individuals over 60 years of age. The project will explore clinical and biological differences between the recently proposed Brain-First and Body-First phenotypes of PD. Patients will undergo detailed clinical evaluation, neuroimaging, and biomarker assessments (including neurodegeneration and neuroinflammation markers). Particular attention will be given to the progression of axial and cognitive symptoms, which represent major contributors to disability. Findings from this study are expected to improve early patient stratification, clarify disease mechanisms, and support the development of precision medicine strategies and future disease-modifying therapies.