HAMP and Huntington disease: Further studies using a large number of HD patients would be necessary to determine the benefit of OIT, optimal levels of serum ferritin to avoid a risk of iron overload, the benefit of IIT in patients who are resistant to OIT, and whether the response to iron therapy is different in HD patients with and without inflammation as well as whether predictive values of ferritin and hepcidin-25 for the response to iron therapy are dependent on inflammation.