MSTN and cardiac hypertrophy: On the other hand, Myocd- and Mstn-encoded proteins (myocardinand myostatin) play a significant role in cardiac morphogenesis, contractility,and heart energy homeostasis.23,24 Myocardin is essentialfor heart development and cardiomyocyte differentiation, but it isalso involved in cardiomyocyte hypertrophy.23 During cardiac hypertrophy, a phenomenon of “fetal gene activation”is given, suggested as a protective physiological response againststress.