According to the Clinical Practice Guideline for CKD-MBD, the serum levels of Ca, P, and PTH in CKD stages 3–5 are recommended to be maintained at a range of 2.1–2.5 mmol/L, 0.87–1.45 mmol/L, and 150–300 pg/ml, respectively. This evidence concerns the gene PTH and Marchiafava-Bignami disease.