FGF13 and left ventricular hypertrophy: First, echocardiography results showed that upon treatment with D‐galactose (Figure2A), myocardial function exhibited abnormalities, characterized by left ventricular hypertrophy, and decreased ejection fraction and fractional shortening, while myocardial FGF13 deficiency mitigated these outcomes (Figure 2B,G; Table S4, Supporting Information).