We found that in obesity-induced cardiac hypertrophy mice, obesity led to increased CARD9 expression, p38 MAPK activation, and the increased expression of the hypertrophy-related genes of GATA4 and MEF2c. Inhibition of p38 MAPK activity then decreased GATA4 and MEF2 expression, but CARD9 expression was unchanged. The gene discussed is GATA4; the disease is obesity due to melanocortin 4 receptor deficiency.