:There are several reasonably-credible reports of an association between hemochromatosis and Parkinson's disease.   E.g., Concurrent hereditary haemochromatosis and idiopathic Parkinson’s disease: a case report series.  I'd have to go back to get the earlier cites,  but I have known about it since the early 1970's, as a graduate student. It may be one of those things that everybody knows about, so it is not "reportable".  If memory serves,  present work on the involvement of iron in PD comes from this source.