FGFR4 and cardiac hypertrophy: FGF23 directly targets cardiac myocytes via the described FGFR4/PLCγ/calcineurin/NFAT signaling pathway and induces cardiac hypertrophy, and potentially other changes in cardiac remodeling, including cardiac fibrosis and altered cardiac metabolism, eventually resulting in reduced heart function (155, 162, 164) (Figure 1).