The amount of soluble klotho protein in the cardiac tissue of CKD patients correlates with the duration of ESRD and the mode of RRT at time of death, and finally, cardiac FGFR4 expression correlates with estimated glomerular filtration rate, mode of RRT at time of death, cumulative time spent on dialysis, and cardiac FGF23 expression levels. This evidence concerns the gene FGF23 and chronic kidney disease.