FGF23 and hyperphosphatemia: Individuals with genetic s.Klotho deficiency exhibit phenotypic characteristics such as bone disease, vascular calcification, increased cardiovascular disease (CVD), elevated levels of fibroblast growth factor 23 (FGF23), hyperphosphatemia, and premature mortality that resemble the accelerated aging phenotype seen in patients with chronic kidney disease (CKD) [2–4].