Complex sentence: Parkinson's disease (PD) is a progressive degenerative disease of the basal ganglia, characterized by the loss of dopaminergic cells of the substantia nigra, pars compacta (SNc).
Split into simpler sentences: Parkinson's disease (PD) is diagnosed in the area of the basal ganglia, as it is a progressive degenerative disease. Pathologically, it is characterized by the loss of dopaminergic cells of the substantia nigra, pars compacta (SNc).