FGFR4 and cardiac hypertrophy: Animal models with elevated serum FGF23 levels, induced by CKD, genetic deletion of klotho, injection of recombinant FGF23 protein, or a high phosphate diet, develop cardiac hypertrophy, which can be blocked by administration of specific inhibitors for FGFR4 or calcineurin (155, 164, 168).