GCH1 and Parkinsonism: The syndrome of dystonia‐parkinsonism can be acquired (medication‐induced, lesion‐associated, toxic, infectious, prion, autoimmune) and genetic (TAF1, PRKRA, ATP7B, GBA, HTT, SLC19A3, ATP1A3, KMT2B, PLA2G6, GCH1, PRNP, and mitochondrial disorders—many of which are associated with iron accumulation).10