KL and left ventricular hypertrophy: iFGF23 induces hypertrophic growth of cardiac myocytes in vitro and left ventricular hypertrophy (LVH) in rodents via FGFR4-mediated activation of the calcineurin/nuclear factor of activated T cells (NFAT) signaling pathway independent of its physiological cofactor klotho, indicating that FGF23 can directly affect the heart (Faul et al., 2011; Grabner et al., 2015).