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Where does Parkinson's disease start? In the brain or gut? Or both? - Neuroscience News
Lewy body disorders, including Parkinson's disease and Lewy body dementia, comprise of two distinct subtypes. One subtype originates in the peripheral nervous system (PNS) of the gut and spreads to the brain. The other originates in the brain, or enters the brain via the olfactory system, before spreading to the brainstem and PNS.