FYI .. restless legs in NOT a sign of low dopamine, though dopamine agonists are prescribed for the symptoms of it. The jury is still out on RLS' causes.

Numerous studies show a deficiency in iron levels in the brain (not serum blood levels, which are usually normal). Interesting because one of the supposed causes of PD is too much iron in the brain. As you are no doubt aware, there are many associations between PD and RLS amongst patients.

Other studies show high levels of glutamine in the brain .. both of these theories has a lot of research behind it but the jury is still out.

And it's similar with PD. The "cause" (if it's singular, which I doubt) is not yet found not controlled. Hell, they cannot even diagnose it definitively .. it's entirely subjective at this point.

No offense intended but you might do better on this board to ask more questions and make fewer definitive statements.