TNNT2 and cardiomyopathy: To explore the possible role of myocardin downregulation in the pathogenesis of cardiomyopathy in Atp6v0d1AKO, we restored cardiac myocardin expression by tail-vein injection of AAV9 virus that expresses myocardin under the control of the cTNT promoter (AAV9-cTnt-Myocd) to Atp6v0d1AKO mice aged 16 weeks (Figure 5D).