Colonoscopic Detection of Phosphorylated Alpha-synuclein for Parkinson's Diagnosis

This study is looking at whether a specific protein marker found in colon tissue — called phosphorylated alpha-synuclein — can be detected through a routine colonoscopy to help diagnose Parkinson's disease earlier and more reliably. This could eventually lead to a simpler, less invasive diagnostic test for Parkinson's. **You may be eligible if...** - You are between 40 and 99 years old - You have a confirmed clinical diagnosis of Parkinson's disease - You are already scheduled to have a routine colonoscopy (for colon cancer screening or to rule out other gut problems) **You may NOT be eligible if...** - You are taking blood thinners (most anticoagulants), though low-dose aspirin or Plavix alone may be allowed - You have a history of colon cancer - You have recently had gastrointestinal illness or surgery - You are pregnant or planning to become pregnant before the colonoscopy - You have significant cognitive impairment that affects your ability to understand the study voluntarily Talk to your doctor to see if this trial is right for you.