GSTM1 and Huntington disease: In fact, Fukushima et al. [35] have showed that serum zinc levels were positively correlated with anemic parameters such as red blood cell (RBC) counts, hemoglobin (Hb), or hematocrit (Ht) levels in HD patients with lower zinc levels than the reference value (<80 mg/dL), and that zinc supplementation with polaprezinc (as 34 mg/day of zinc) could improve anemia and reduce ESA doses in those patients.