Okada et al., in their prospective, case-control study of 26 patients with chronic renal failure on high flux hemodialysis (HD) and human recombinant erythropoietin suffering from PN, compared B6 supplementation at a dose of 60 mg/day (n = 14) versus B12 supplementation at a dose of 500 μg/day (n = 12) [27]. The gene discussed is EPO; the disease is chronic kidney disease.