We’ve done a post on our blog about the genetics of Parkinson’s with Professor Huw Morris that I think you may find very informative, considering your queries. He also talks about ongoing research where people can join in the effort to better understand the genetics of Parkinson’s. This would be free and more likely to help progress Parkinson’s research in the area (23andme is a global company and not focused solely on Parkinson’s, and results from Parkinson’s researchers are more likely to be published and shared).
You can find this information here if you want to have a read.
I hope you find this useful.