In the present study, we created the TRACP-5b/intact PTH (iPTH) ratio as an index of bone responsiveness to PTH, categorized into tertiles (low, medium, and high), and aimed to compare clinical and laboratory factors between the low, medium, and high TRACP-5b/iPTH ratio groups of patients undergoing chronic HD. The gene discussed is ACP5; the disease is Huntington disease.