Colonic Tissue Biopsy Detection of Phosphorylated Alpha-synuclein for Parkinson's Diagnosis or REM Sleep Behavior Disorder

The goal of this observational study is to learn whether tissue samples taken from the colon during routine colonoscopy can detect signs of Parkinson's disease or REM Sleep Behavior Disorder (RBD). The main question it aims to answer is:

Can doctors find a protein called alpha-synuclein in colon tissue samples from people with Parkinson's disease and RBD?

Currently, Parkinson's disease is diagnosed by observing symptoms like tremors and movement problems and RBD by loss of muscle atonia during REM sleep, but by then the disease has already progressed significantly. Earlier detection could help doctors start treatment sooner.