Biomarkers in Parkinson's

What is a biomarker? Which ones do we have? Are there tools available for identifying risk? Risk of diagnosis? Risk of progression? Risk of death? If there are, why don't we use them in clinic?
2024 update: SYN-ONE skin biopsies are the front-runner for a Parkinson biomarker these days (cndlifesciences.com/syn-one-t...)
This is a clip taken from the online Parkinson School course, "How do we know what we know?"
www.Parkinson-School.com

[@honeyhonesty3784]

Thanks for your service for us. Passion, intelligence, honesty and goodwill are shining

[@FatherSebastiaan]

this is old because the MJF found a biomarker in April 2023