Fibroblast growth factor 23 (FGF-23), dentin matrix protein 1 (DMP1), and sclerostin are osteocyte-secreted proteins that become elevated during the early stages of CKD when the circulating concentrations of calcium, phosphate (P), PTH, and active vitamin D are still within the normal range [7,8]. Here, FGF23 is linked to chronic kidney disease.