KL and chronic kidney disease: Bearing in mind klotho/FGF23 axis disturbance, the klotho deficiency, and high FGF23 levels, in patients with CKD, it has been suggested that the klotho/FGF23 axis could be not only diagnostic and prognostic biomarkers of CKD and CV disease but could be treatment targets as they contribute to the CKD progression and development of CV disease as complication [122].