TF and Iron deficiency anemia: Moreover, neuropathological studies have found decreased concentrations of iron, ferritin, and other proteins related with iron homeostasis in the substantia nigra of RLS patients.32–36 The results of studies assessing cerebrospinal fluid and serum/plasma levels of iron, ferritin, and transferrin are controversial (revised in).2 Several data in experimental models resembling RLS suggest an important interaction between iron deficiency and the dopaminergic system in the pathogenesis of RLS (revised in).2