Looking for Parkinson’s-related signs in gut nerve cells

Inclusion Criteria: * Age 45-75 years old * Parkinson's Disease defined by the modified UK Parkinson's Disease Society Brain Bank criteria, at risk for the development of Parkinson's disease including REM sleep behavior disorder and/or at least one first degree relative with PD or related disorder, and diseases related to Parkinson's disease including the synucleinopathies Lewy Body Dementia and Multiple System Atrophy. * Baseline Hoehn \& Yahr score 1-4 * No contraindications to undergoing screening colonoscopy * Able to give informed consent for study participation Exclusion Criteria: * Clinical features suggestive of a neurodegenerative diagnosis other than synucleinopathy. * Diagnosis of primary mitochondrial disorder, epilepsy, stroke, multiple sclerosis or other neurodegenerative diseases such as Alzheimer's disease, Progressive Supranuclear Palsy (PSP), and Corticobasal syndrome. * Significant concomitant medical disease limiting life expectancy to less than 24 months from study inclusion, or significant and serious concomitant medical disease that is poorly controlled * Signs of active malignant disease or other clinically relevant abnormality on chest x-ray * Active or untreated gastrointestinal disease * Inability to temporarily stop anti-platelet agents or other anti-coagulants without significant risk * Known substance abuse (recent history of abuse of alcohol or other drugs such as barbiturates, cannabinoids and amphetamines) within last 5 years * Contraindication to colonoscopy or associated anesthesia * Pregnancy * In the opinion of the investigator, any other condition regarded as making subject unsuitable for the study