There are some interesting developments going on in the investigation of alpha-synuclein's role in PD.

Turns out that this protein which we end up with an excess of impairs our neurotransmitter function long before cells start to die off and there is evidence that it may accumulate in our intestines before motor symptoms surface causing...constipation. This could herald start of the disease process.

This is the promising part:

The loss of function n Parkinson’s disease that is attributed to loss of neurons in the brain may in part be due to impaired signaling, Edwards suggests.

“Even people with advanced Parkinson’s still have a substantial number of dopamine-producing neurons that remain. Our prediction is that even the neurons that survive don’t work very well, due to functional impairment at synapses.”

This means that instead of all our neurons dying off, some just may be signal impaired? If they control the alpha-synuclein proliferation, it might restore neurons to a fully functional state?

Parkinson’s Disease Protein Impedes Nerve Signaling Long Before Brain Cells Die -Research at UCSF