Appendix may be related to Parkinson’s disease

Parkinson’s disease may start in the appendix, not the brain. People are less likely to get the condition if they had their appendix out decades previously. And a toxic compound found in the brains of people with this disease has now been spotted in the appendix.

Source(s):

http://stm.sciencemag.org/content/10/465/eaar5280

https://www.newscientist.com/article/2184110-parkinsons-disease-may-start-in-the-appendix-and-travel-to-the-brain/